Based on the modeling of the central emission-line width measured over subarcsecond apertures with the Hubble Space Telescope, we present stringent upper bounds on the mass of the central supermassive black hole, M_BH, for a sample of 105 nearby galaxies (D < 100 Mpc) spanning a wide range of Hubble types (E-Sc) and values of the central stellar velocity dispersion, σ_c (58-419 km/s). For the vast majority of the objects, the derived M_BH upper limits run parallel and above the well-known M_BH-σ_c relation independently of the galaxy distance, suggesting that our nebular line-width measurements trace rather well the nuclear gravitational potential. For values of σc between 90 and 220 km/s, 68% of our upper limits falls immediately above the M_BH-σ_c relation without exceeding the expected M_BH values by more than a factor 4.1. No systematic trends or offsets are observed in this σ_c range as a function of the galaxy Hubble type or with respect to the presence of a bar. For 6 of our 12 M_BH upper limits with σ_c < 90 km/s, our line-width measurements are more sensitive to the stellar contribution to the gravitational potential, either due to the presence of a nuclear stellar cluster or because of a greater distance compared to the other galaxies at the low-σ_c end of the M_BH-σ_c relation. Conversely, our M_BH upper bounds appear to lie closer to the expected M_BH in the most massive elliptical galaxies with values of σc above 220 km/s. Such a flattening of the M_BH-σ_c relation at its high-σ_c end would appear consistent with a coevolution of supermassive black holes and galaxies driven by dry mergers, although better and more consistent measurements for σ_c and K-band luminosity are needed for these kinds of objects before systematic effects can be ruled out.
Upper limits on the masses of 105 supermassive black holes from Hubble Space Telescope/Space Telescope Imaging Spectrograph archival data
BEIFIORI, ALESSANDRA;CORSINI, ENRICO MARIA;DALLA BONTA', ELENA;PIZZELLA, ALESSANDRO;BERTOLA, FRANCESCO
2009
Abstract
Based on the modeling of the central emission-line width measured over subarcsecond apertures with the Hubble Space Telescope, we present stringent upper bounds on the mass of the central supermassive black hole, M_BH, for a sample of 105 nearby galaxies (D < 100 Mpc) spanning a wide range of Hubble types (E-Sc) and values of the central stellar velocity dispersion, σ_c (58-419 km/s). For the vast majority of the objects, the derived M_BH upper limits run parallel and above the well-known M_BH-σ_c relation independently of the galaxy distance, suggesting that our nebular line-width measurements trace rather well the nuclear gravitational potential. For values of σc between 90 and 220 km/s, 68% of our upper limits falls immediately above the M_BH-σ_c relation without exceeding the expected M_BH values by more than a factor 4.1. No systematic trends or offsets are observed in this σ_c range as a function of the galaxy Hubble type or with respect to the presence of a bar. For 6 of our 12 M_BH upper limits with σ_c < 90 km/s, our line-width measurements are more sensitive to the stellar contribution to the gravitational potential, either due to the presence of a nuclear stellar cluster or because of a greater distance compared to the other galaxies at the low-σ_c end of the M_BH-σ_c relation. Conversely, our M_BH upper bounds appear to lie closer to the expected M_BH in the most massive elliptical galaxies with values of σc above 220 km/s. Such a flattening of the M_BH-σ_c relation at its high-σ_c end would appear consistent with a coevolution of supermassive black holes and galaxies driven by dry mergers, although better and more consistent measurements for σ_c and K-band luminosity are needed for these kinds of objects before systematic effects can be ruled out.File | Dimensione | Formato | |
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