BH mass determination of low redshift quasars

Labita, M.; Treves, A.; Falomo, R.; Scarpa, Riccardo; Uslenghi, M.

doi:10.1063/1.2774953

Cited by 33 publications

(66 citation statements)

References 7 publications

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“…We have also obtained the absolute B-band magnitude ( ) of the objects from Veron-Cetty & Veron (2006). The M B, QSO absolute R-band magnitude of the host galaxies ( ) is avail-M R, gal able for six of them, which have been imaged by the HST Wide Field Planetary Camera 2 with a broadband filter (Labita et al 2006). Using a formula based on the virial theorem (Labita et al 2006), the BH masses ( ) were estimated from the C iv M BH FWHM and the continuum luminosity ( ) at 1350 , which lL A l are available from the modeling of the FOS spectra (Kuraszkiewicz et al 2002(Kuraszkiewicz et al , 2004.…”

Section: Samplementioning

confidence: 99%

“…The M B, QSO absolute R-band magnitude of the host galaxies ( ) is avail-M R, gal able for six of them, which have been imaged by the HST Wide Field Planetary Camera 2 with a broadband filter (Labita et al 2006). Using a formula based on the virial theorem (Labita et al 2006), the BH masses ( ) were estimated from the C iv M BH FWHM and the continuum luminosity ( ) at 1350 , which lL A l are available from the modeling of the FOS spectra (Kuraszkiewicz et al 2002(Kuraszkiewicz et al , 2004. Our BH mass results are in agreement (5): Host galaxy absolute R-band magnitude (after k-correction and passive evolution correction; following Labita et al 2006).…”

Section: Samplementioning

confidence: 99%

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A Common Origin for Quasar Extended Emission-Line Regions and Their Broad-Line Regions

Stockton

2007

ApJ

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We present a correlation between the presence of luminous extended emission-line regions (EELRs) and the metallicity of the broad-line regions (BLRs) of low-redshift quasars. The result is based on ground-based [O iii] l5007 narrowband imaging and Hubble Space Telescope UV spectra of 12 quasars at . Quasars 0.20 ≤ z ≤ 0.45 showing luminous EELRs have low-metallicity BLRs ( ), while the remaining quasars show typical Z Շ 0.6 Z , metal-rich gas ( ). Previous studies have shown that EELRs themselves also have low metallicities). The correlation between the occurrence of EELRs and the metallicity of the BLRs, strengthened Z Շ 0.5 Z , by the subsolar metallicity in both regions, indicates a common external origin for the gas, almost certainly from the merger of a gas-rich galaxy. Our results provide the first direct observational evidence that the gas from a merger can indeed be driven down to the immediate vicinity (!1 pc) of the central black hole.

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Section: Samplementioning

confidence: 99%

Section: Samplementioning

confidence: 99%

A Common Origin for Quasar Extended Emission-Line Regions and Their Broad-Line Regions

Stockton

2007

ApJ

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“…While the possible role of radiation pressure in measurement of black hole masses is an important issue, it has no direct bearing on the present discussion, which is about measuring time delays. Similarly, there is still active discussion about the mean value of the scaling factor f (e.g., Onken et al 2004;Labita et al 2006;Woo et al 2010;Graham et al 2011) that is beyond the scope of this contribution. 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 2000Kaspi et al , 2005) that allows us to use the luminosity as a surrogate for the BLR size in Equation (3) and thus estimate the masses of black holes in AGNs from individual spectra Vestergaard 2002;McLure & Jarvis 2002Kollmeier et al 2006;Shen et al 2008).…”

Section: Introductionmentioning

confidence: 99%

An Alternative Approach to Measuring Reverberation Lags in Active Galactic Nuclei

Kochanek

Peterson

2011

ApJ

376

543

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Motivated by recent progress in the statistical modeling of quasar variability, we develop a new approach to measuring emission-line reverberation lags to estimate the size of broad-line regions (BLRs) in active galactic nuclei. Assuming that all emission-line light curves are scaled, smoothed, and displaced versions of the continuum, this alternative approach fits the light curves directly using a damped random walk model and aligns them to recover the time lag and its statistical confidence limits. We introduce the mathematical formalism of this approach and demonstrate its ability to cope with some of the problems for traditional methods, such as irregular sampling, correlated errors, and seasonal gaps. We redetermine the lags for 87 emission lines in 31 quasars and reassess the BLR size-luminosity relationship using 60 Hβ lags. We confirm the general results from the traditional crosscorrelation methods, with a few exceptions. Our method, however, also supports a broad range of extensions. In particular, it can simultaneously fit multiple lines and continuum light curves which improves the lag estimate for the lines and provides estimates of the error correlations between them. Determining these correlations is of particular importance for interpreting emission-line velocity-delay maps. We can also include parameters for luminosity-dependent lags or line responses. We use this to detect the scaling of the BLR size with continuum luminosity in NGC 5548.

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“…For Seyfert galaxies, BH masses range between ∼10 6 M and a few 10 7 M (e.g., Greenhill et al 1997b;Herrnstein et al 1999;Henkel et al 2002), while masses in QSOs can reach 10 9 M or more (e.g., Labita et al 2006;Vestergaard et al 2008). Tarchi et al (2007) suggest that clouds in a disk with large rotational velocity and small galactocentric radius like NGC 4258 might not be stable in the vicinity of such a large BH mass.…”

Section: Bh Mass and Accretion Diskmentioning

confidence: 99%

A SEARCH FOR H₂O MEGAMASERS IN HIGH-zTYPE-2 ACTIVE GALACTIC NUCLEI

Bennert¹,

Barvainis²,

Henkel³

et al. 2009

ApJ

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We report a search for H 2 O megamasers in 274 SDSS type-2 active galactic nuclei (AGNs; 0.3 < z < 0.83), half of which can be classified as type-2 quasi-stellar objects (QSOs) from their [O iii] 5007 luminosity, using the Robert C. Byrd Green Bank Telescope (GBT) and the Effelsberg 100 m radio telescope. Apart from the detection of the extremely luminous water vapor megamaser SDSS J080430.99+360718.1, already reported by Barvainis & Antonucci, we do not find any additional line emission. This high rate of nondetections is compared to the water maser luminosity function created from the 78 water maser galaxies known to date and its extrapolation toward the higher luminosities of "gigamasers" that we would have been able to detect given the sensitivity of our survey. The properties of the known water masers are summarized and discussed with respect to the nature of high-z type-2 AGNs and megamasers in general. In the Appendix, we list 173 additional objects (mainly radio galaxies, but also QSOs and galaxies) that were observed with the GBT, the Effelsberg 100 m radio telescope, or Arecibo Observatory without leading to the detection of water maser emission.

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BH mass determination of low redshift quasars

Cited by 33 publications

References 7 publications

A Common Origin for Quasar Extended Emission-Line Regions and Their Broad-Line Regions

A Common Origin for Quasar Extended Emission-Line Regions and Their Broad-Line Regions

An Alternative Approach to Measuring Reverberation Lags in Active Galactic Nuclei

A SEARCH FOR H₂O MEGAMASERS IN HIGH-zTYPE-2 ACTIVE GALACTIC NUCLEI

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BH mass determination of low redshift quasars

Cited by 33 publications

References 7 publications

A Common Origin for Quasar Extended Emission-Line Regions and Their Broad-Line Regions

A Common Origin for Quasar Extended Emission-Line Regions and Their Broad-Line Regions

An Alternative Approach to Measuring Reverberation Lags in Active Galactic Nuclei

A SEARCH FOR H2O MEGAMASERS IN HIGH-zTYPE-2 ACTIVE GALACTIC NUCLEI

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A SEARCH FOR H₂O MEGAMASERS IN HIGH-zTYPE-2 ACTIVE GALACTIC NUCLEI