Constraints on Broad Line Quasar Black Hole Masses, Eddington Ratios, and Lifetimes

Constraints on Broad Line Quasar Black Hole Masses, Eddington

Ratios, and Lifetimes

Brandon C. Kelly (CfA)

Marianne Vestergaard (DARK, Denmark), Xiaohui Fan (Arizona), Philip Hopkins (Berkeley), Lars Hernquist

(CfA), & Aneta Siemiginowska (CfA)

3/10/10 Brandon Kelly, [email protected]

Black Hole Growth and Galaxy Evolution

Black Hole Growth and Galaxy Evolution

• Tight correlation between MBH and host galaxy bulge properties implies that supermassive black holes (SMBH) and galaxy evolution is linked (e.g., Merritt & Ferrarese 2001, Tremaine et al. 2002)

• Can be explained if black hole growth is self-regulated (e.g., Wyithe & Loeb 2003, Di Matteo et al. 2005)

• If growth is SR, then broad line phase for bright quasars occurs at end of growth


Aller & Richstone (2007)

What do We Hope to Learn from Studying the Broad Line Quasar SMBH Mass and Eddington Ratio Distributions?

What do We Hope to Learn from Studying the Broad Line Quasar SMBH Mass and Eddington Ratio Distributions?

• Distribution and Evolution of SMBH Mass and L / Ledd is a fundamental observational quantity for comparing with theoretical models

• Can compare with local mass function of all SMBHs to estimate lifetime of BLQSO phase

• Investigate how much growth occurs during BLQSO phases, test self-regulated growth model


Correcting for Mass Uncertainty and Incompleteness (Kelly et al. 2009)

Correcting for Mass Uncertainty and Incompleteness (Kelly et al. 2009)


• Can derive mass estimates from L and FWHM (e.g., Vestergaard & Peterson 2006)

• Mass estimates have a large statistical scatter (~0.4 dex), broaden inferred BHMF

• Complicated incompleteness, even high mass end can be incomplete

Sample SummarySample Summary

• Used the SDSS DR3 Sample of Richards et al. (2006) with measurements taken from Vestergaard et al.(2008)

• Only kept objects at 1 < z < 4.5• Used Mg II for 1 < z < 1.6, and C IV for z > 1.6• Left with ~ 10,000 sources


Quasar BHMF at 1 < z < 4.5Quasar BHMF at 1 < z < 4.5


Black Solid: Our Estimated BHMFsGreen Solid: Best-fit BHMFDashed Black : Local BHMF for all SMBHs (Merloni & Heinz 2008)Red Solid: BHMF from Vestergaard et al.(2008)

Volonteri & Natarajan (2009)Volonteri & Natarajan (2009)

Eddington Ratio Distribution and Fractional Growth

Eddington Ratio Distribution and Fractional Growth


Most Broad Line Quasars are not accreting at or near the Eddington Limit

Most Broad Line Quasars are not accreting at or near the Eddington Limit

Most of the contribution to the localBH mass density is from objects that we currently see as obscured

Most of the contribution to the localBH mass density is from objects that we currently see as obscured

Inferred Lifetime of Broad Line PhaseInferred Lifetime of Broad Line Phase


• Lifetime too short to grow a BH seed of MBH ~ 106 MSUN to MBH ~ 109 MSUN

• Lifetime + L / Ledd Distribution Imply that most growth occurred in an earlier obscured phase of Eddington-limited growth

• Lifetime too short to grow a BH seed of MBH ~ 106 MSUN to MBH ~ 109 MSUN

• Lifetime + L / Ledd Distribution Imply that most growth occurred in an earlier obscured phase of Eddington-limited growth

Maximum Mass of a SMBHMaximum Mass of a SMBH


• If SMBH growth is self-regulated, this should be representative of the most massive SMBH

• Consistent with maximum mass seen in cosmological simulations (Sijacki et al. 2009) and that expected from self-regulation arguments (Natarajan & Treister 2009)

• If SMBH growth is self-regulated, this should be representative of the most massive SMBH

• Consistent with maximum mass seen in cosmological simulations (Sijacki et al. 2009) and that expected from self-regulation arguments (Natarajan & Treister 2009)

Sijacki et all (2009)

Summary• First work to rigorously and self-consistently correct

for statistical uncertainty and incompleteness in the broad line quasar mass function

• BLQSO BHMF qualitatively in agreement with cosmological model of self-regulated black hole growth

• Most BL quasars are not accreting at or near L / Ledd

• SMBHs cannot experience all of their growth in a BL phase

• Maximum SMBH mass is ~ 1010 – 1011 MSUN

• Uncertainty in mass estimates may be ~ 0.2 dex, or correlated with luminosity


How uncertain are the Mass Estimates?

How uncertain are the Mass Estimates?

Assuming Scatter of 0.4 dexAssuming Scatter of 0.4 dex When we fit the ScatterWhen we fit the Scatter


Red is the modelDistribution

Black is the observeddistribution

Standard value of 0.4 dex implies a mass estimate distribution that is too broad, implies:

- Statistical error is correlated with luminosity? (Shen & Kelly 2010)- Uncorrected radiation pressure? (Marconi et al. 2008)- Broad line mass estimates are meaningless at this L and z?

Standard value of 0.4 dex implies a mass estimate distribution that is too broad, implies:

- Statistical error is correlated with luminosity? (Shen & Kelly 2010)- Uncorrected radiation pressure? (Marconi et al. 2008)- Broad line mass estimates are meaningless at this L and z?

Future workFuture work

• Incorporate more flexible L / Ledd distribution• Investigate if error in mass estimates is correlated

with luminosity, and include in application to DR7 data set (Shen & Kelly, in prep)

• Apply technique to COSMOS and other multiwavelength data sets to better determine Eddington ratio distribution and BHMF (Kelly & Trump, et al.)

• Reverberation mapping of higher z and L sources to better determine uncertainties (Elvis and Trump, et al.)


Mass-Luminosity Plane


Downsizing of SMBHsDownsizing of SMBHs


Documents

Constraints on Broad Line Quasar Black Hole Masses, Eddington Ratios, and Lifetimes