The Radius-Luminosity Relationship for Active Galactic Nuclei: The Effect of Host-Galaxy Starlight on Luminosity Measurements

By M. Bentz, B. Peterson, R. Pogge, M. Vestergaard, C. Onken. 2006

135 citations recorded by the source corpus.

We have obtained high-resolution images of the central regions of 14 reverberation-mapped active galactic nuclei (AGNs) using the Hubble Space Telescope Advanced Camera for Surveys High Resolution Camera to account for host-galaxy starlight contamination of measured AGN luminosities. We measure the host-galaxy starlight contribution to the continuum luminosity at 5100 Å through the typical ground-based slit position and geometry used in the reverberation-mapping campaigns. We find that removing the starlight contribution results in a significant correction to the luminosity of each AGN both for lower luminosity sources, as expected, but also for the higher luminosity sources such as the PG quasars. After accounting for the host galaxy starlight, we revisit the well-known broad-line region radius-luminosity relationship for nearby AGNs. We find the power-law slope of the relationship for the Hβ line to be 0.518 ± 0.039, shallower than what was previously reported and consistent with the slope of 0.5 expected from the naive theoretical assumption that all AGNs have, on average, the same ionizing spectrum and the same ionization parameter and gas density in the Hβ line-emitting region.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/b16fb1b6ab4d9d2b37c33990e4c2f6488b6e942f

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In Astronomy and Astrophysics

1. D. M. Alexander
2. Jenny E. Greene
3. Luis C. Ho
4. P. Hopkins
5. Mara Salvato
6. L. Hernquist
7. T. Treu
8. P. Capak

In Instrumentation

1. Mara Salvato
2. P. Capak
3. D. M. Alexander
4. Jenny E. Greene
5. A. Koekemoer
6. Luis C. Ho
7. A. Renzini
8. T. Treu

Citations in the corpus

• The Mass Function of Active Black Holes in the Local Universe (2007, background): “Most recently, Bentz et al. (2006) find a shallower radius-luminosity slope (0.52±0.04 rather than the 0.64±0.02 assumed here), which would lead to a narrower distribution in BH mass.”
• REVERBERATION MAPPING MEASUREMENTS OF BLACK HOLE MASSES IN SIX LOCAL SEYFERT GALAXIES (2010, background): “…of these local relationships is secure (i.e., observational scatter minimized) and any intrinsic scatter is well characterized (see, e.g., Bentz et al. 2006, 2009a,b; Graham 2007; Gültekin et al. 2009; Woo et al. 2010, for recent efforts to improve scaling relation calibration and…”
• THE LOW-LUMINOSITY END OF THE RADIUS–LUMINOSITY RELATIONSHIP FOR ACTIVE GALACTIC NUCLEI (2013, methodology): “Based on previous work (Kaspi et al. 2000, 2005; Bentz et al. 2006b, 2009a), we expect the form of the RBLR–”
• AN ALTERNATIVE APPROACH TO MEASURING REVERBERATION LAGS IN ACTIVE GALACTIC NUCLEI (2010, methodology): “Second, reverberation studies have established a tight empirical relationship between the BLR size and the AGN continuum luminosity (Kaspi et al. 1996; Kaspi et al. 2000, 2005; Bentz et al. 2006, 2009) that allows us to use the luminosity as a surrogate for the BLR size in eq.”
• ON THE COSMIC EVOLUTION OF THE SCALING RELATIONS BETWEEN BLACK HOLES AND THEIR HOST GALAXIES: BROAD-LINE ACTIVE GALACTIC NUCLEI IN THE zCOSMOS SURVEY (2009, methodology): “We measure black hole masses by applying the “virial” or “empirically calibrated photo- ionization” method (Wandel et al. 1999; Kaspi et al. 2000; Peterson et al. 2004; Bentz et al. 2006) to the Mg IIλ2798Å broad emission line.”
• REVERBERATION MEASUREMENTS OF THE INNER RADIUS OF THE DUST TORUS IN 17 SEYFERT GALAXIES (2014, unknown): “We enlarged the data for reverberation radii of the BLR by adding the results of the recent reverberation observations for Hβ emission lines (Bentz et al. 2006b, 2007, 2009a,b; Denney et al. 2010; Barth et al. 2011a,b; Grier et al. 2012b).”
• A New Sample of Low-Mass Black Holes in Active Galaxies (2007, methodology): “Along these lines, we should note that the revised radiusluminosity relation slope (Bentz et al. 2006) substantially increases the virial masses at low BH mass, which in turn increases the apparent flattening in theMBH − σ∗ relation slope at low mass previously reported by Greene & Ho (2006).”
• A Reverberation-based Mass for the Central Black Hole in NGC 4151 (2006, unknown): “Column (5) is the mean flux and standard deviation of the light curve, not including a correction for host-galaxy starlight, which, following the methods of Bentz et al. (2006) for this slit geometry, is measured to be Fgal(5100Å) = (2.11±0.18)×10−14 ergs s−1 cm−2 Å−1.”
• Measuring the Masses of Supermassive Black Holes (2014, background): “…a consortium of astronomers primarily in eastern Europe, Mexico, and Germany (e.g., Shapovalova et al. 2010; Popovi´c et al. 2011; Shapovalova et al. 2012) and by the author's group of collaborators (Bentz et al. 2006b; Denney et al. 2006; Bentz et al. 2007; Denney et al. 2010; Grier et al. 2012b).”
• Black Holes in Pseudobulges and Spheroidals: A Change in the Black Hole-Bulge Scaling Relations at Low Mass (2008, methodology): “With measured BLR radii, it is possible to calibrate an empirical relation between the AGN luminosity and the BLR size (e.g., Kaspi et al. 2005; Bentz et al. 2006), and from this relation to estimate BH masses from single-epoch spectroscopy.”