Census of Active Super Massive Black HolesActive Super Massive Black Holes

in the Era of Violent Growth

Masayuki Akiyama (Tohoku Univ )Masayuki Akiyama (Tohoku Univ.)秋山 正幸 (東北大学)

2013/01/27 Hokkaido University

Black hole mass function (BHMF)and

Eddington radio distribution function (ERDF) of AGNs at z~1.4

Masayuki Akiyama, Kazuya Nobuta (Tohoku Univ.)fYoshihiro Ueda (Kyoto Univ.), Mike Watson (Univ. of Leicester),

John Silverman (IPMU),SXDSmembers FMOS GTO membersSXDS members, FMOS GTO members

Nobuta, MA, et al. ApJ, 761, 143p

Relation between BH mass vs. bulge “mass”Massi e gala ies ha e a s per massi e BH at their center and the mass of theMassive galaxies have a super massive BH at their center and the mass of the SMBH correlates with the mass of its host bulge. We want to understand the origin of the SMBH by qualitatively revealing1) How the SMBHs have grown in the history of the universe ?) g y2) What links between the evolutions of SMBHs and galaxies ?

McConnell et al. 20111)

2)

1)

Schematic View of Growth History of Super Massive BHs

Gas accretion from galaxy scale

= “Feeding”

Merging

Merging

Feeding

Merging

SEED BHsOutflow etc. affecting galaxy scale properties

= “Feedback”

SEED BHsIn young

“spheroids” SMBHs sitting in “spheroids” consists

with old starsAccretion growth phase can be

observed as various types of AGNs

Growth history of Super Massive BHsGas accretion

from galaxy scale= “Feeding”

Outflow etc. affecting galaxy scale properties= “Feedback”

In order to qualitatively understand the growth history, for each SMBHs we want to know

1. Accretion rate ~ Bolometric luminosity / Radiation efficiency2. Black hole mass3 G th ti l A ti t / M Eddi t ti3. Growth timescale ~ Accretion rate / Mass = Eddington ratio4. Duty cycle ~ Fraction of galaxies with active black hole

Active BH Mass Function and Eddington Ratio Distribution Function of Broad-line AGNs

in the Local Universe

Kelly et al. 2012Schulze and Wisotzki 2010Points: observedLines: observational limit corrected by Maximum Likelihood

Rather steep active BH mass function and Eddington ratio distribution

Lines: observational limit corrected by Maximum Likelihood method assuming constant ERDF for the sample mass range

p gfunction mean no typical active black hole mass or no typical Eddingtonratio in the local universe.

Cosmological Evolution of Number Density of AGNs

Low-luminosity AGN

S f tSeyferts(< 1 Msolar/yr)

Luminous QSOs(> 1 Msolar/yr)(> 1 Msolar/yr)

Ueda, MA, et al. in prep.p p

Based on X-ray selected AGNs from Subaru-XMM Newton Deep Survey and other X-ray surveys.

Accretion rate distribution at z=1-2

~ 1 Msolar/yr ~ 1 Msolar/yr

Ueda, MA, et al. in prep.

Luminosity function reflects the accretion rate distribution.

L L 44 5 ( 1) d t 1 M l / ith di tiLog Lx=44.5 (erg s-1) corresponds to 1 Msolar/yr with radiation efficiency of 0.1.

Era of Violent Growth of SMBHs

Hard X-ray luminosity density reflects the total accretion rate density at each redshift, like UV or IR luminosity density reflects the star formation rate density at yeach redshift.

The peak of the hard X-ray luminosity density suggests rapid growth of SMBHs happened at z=1-2.

Aird et al. 2010

SXDS sample

30’ diameter

SXDS sample

866 and 645 X-ray sources are detected in XMM-Newton images in the 0.5-2.0 and 2.0-10.0 keV bands (Ueda et al. 2008).

945 sources are covered by the deep Subaru/Suprime-cam images (Furusawa et al. 2008).

Removing candidates of clusters of galaxies and galactic stars, 896 sources remain as candidates of AGNs.

Optical spectroscopic observations cover: 590 sources

FMOS GTO NIR spectroscopic observations cover: 851 sourcesp p

586 sources have spectroscopic-redshifts

304 out of 310 remaining sources have secure photometric redshifts determined with photometry in the wavelength range between 1500A (GALEX) to 8um (Spitzer IRAC). (3.6 um IRAC data

f f fare crucial for identification of the X-ray sources.)

SXDS AGNs at z=1-2

For black hole mass function, we limit the sample within the redshift range between 1.18<z<1.68. There areBroad-line AGN : with zspec 118 objects, zphot only 10 objectsNarrow-line AGN : with zspec 66 objects, zphot only 92 objects

Virial Black Hole Mass Estimationwith L-BLR Radius relationwith L BLR Radius relation

We use the black hole mass estimation from Vestergaard & Osmer (2009) with FWHM of MgII broad emission line and 3000Amonochromaticwith FWHM of MgII broad-emission line and 3000A monochromatic luminosity.

The relation is calibrated with reverberation mapping AGN black hole mass pp gwith H-beta broad-line line width. It assumes,

Luminosity ‒ BLR radius relationBLR is virializedLocal MBH-Mbulge relation for AGN is consistent with MBH-Mbulgerelation of galaxies

“Si l h” bl k h l i h 0 4 0 5d“Signle-epoch” black hole mass estimate can have 0.4-0.5dex scatter against MBH determined with reverberation mapping.

MgII FWHM measurements

With optical spectroscopic data.(188 objects in total) 97 objects out of 118 broad-line AGNs at z=1.18-1.68 j j

Halpha FWHM with FMOS

(81 objects in total) 19 additional objects out of 21 broad-line AGNs at z=1.18-1.68 w/o MgII FWHM measurement

Halpha FWHM

(81 objects in total) 19 additional objects out of 21 broad-line AGNs at z=1.18-1.68 w/o MgII FWHM measurementg

FWHM vs. continuum luminosityyBroad-line AGNs in 1.18 < z <1.68All broad-line AGNs

Broad-line AGNs in SXDS (black) and SDSS (gray scale)Red open squares indicate broad-line AGNs whose FWHM is estimated with Halpha emission line.estimated with Halpha emission line.

Lack of AGNs with FWHM < 2000km/s ?

Black Hole Mass and Eddington RatioPlotted only broad-line AGNs in the redshift range 1.18 < z <1.68

D i li iDetection limit

B d li AGN i SXDS ( i ) d SDSS ( )Broad-line AGNs in SXDS (points) and SDSS (contour)Lack of high Eddington ratio AGNs with 10^7 Msolar ?

Active Super Massive Black Hole Mass Function

SXDS 1.18 < z <1.68

Filled and open circles are binned BHMF estimated by Vmax method with soft and hard band samples, respectively.

Eddington Ratio Distribution Function

SXDS 1.18 < z <1.68

Filled and open circles are binned ERDF estimated by Vmax methodFilled and open circles are binned ERDF estimated by Vmax method with soft and hard band samples, respectively.

Active Super Massive Black Hole Mass Function

SXDS 1.18 < z <1.68SXDS 1.18 < z <1.68

Lines are “corrected “ BHMF and ERDF from Maximum Likelihood estimation corrected for the detection limits assuming constant ERDF regardless of the black hole mass.

Solid: double-power-law BHMF, Dotted: Schechter BHMFG l l RD R d S h h RDGreen: log-normal ERDF, Red: Schechter ERDF

Active BHMF at z~1.4 compared with SDSS resultsp

SXDS 1 18 1 68SXDS 1.18 < z <1.68

Z=1.4SDSS DR7 (Shen & Kelly 2012)

Circles: binned estimates with VmaxCircles: binned estimates with VmaxSolid lines: esimated with Bayesian method

Evolution of active BHMF from z=1.4 to z=0

SXDS 1.18 < z <1.68

Z=0 from ESO/Hamburg fromSchultz-Wisotzki 2010

z~1.4 active BH mass function has a higher number density above 10^8 l b l b d b l h h h hMsoloar but a lower number density below that mass range than that in the

local Universe. The evolution may be indicative of a down-sizing trend of accretion activity among the SMBH population.

Evolution of ERDF from z=1.4 to z=0

SXDS 1.18 < z <1.68

Z=0 from ESO/Hamburg fromSchultz-Wisotzki 2010Schultz-Wisotzki 2010

The evolution of ERDF from z=1.4 to z=0 indicates that the fraction of AGNs with accretion rate close to the Eddington-limit is higher at higher redshifts.

BHMF and ERDF on the MBH-ER planeExpected number density on the MBH ER plane (BHMF x ERDF xExpected number density on the MBH-ER plane (BHMF x ERDF x selection function) is shown with gray scale.

BHMFBHMF

ERDF

Detection Limit

Growth of SMBH from z=6 to z=1.4 to z=0

Z=0 from ESO/Hamburg fromSchultz-Wisotzki 2010

SXDS 1.18 < z <1.68Schultz-Wisotzki 2010

Z=6 fromWillott et al 2010Willott et al. 2010

30 times mass evolution in 3.5 Gyr periodLambda Edd * duty cycle ~ 0 06Lambda_Edd * duty cycle ~ 0.06

What does the double power-law of the AGN LF mean ?What drives the evolution of the LF of AGNs ?What drives the evolution of the LF of AGNs ?

U d MA l iUeda, MA, et al. in prep.

Hard X-ray luminosity function at z=1.4 Recovered by the best-fit BHMF and ERDFby the best fit BHMF and ERDF

The luminosity function of AGNs is the convolution of the BHMF and ERDF, therefore we can constrain the shapes of BHMF and ERDF further by using the luminosity function determined from a combination of various AGN samples.luminosity function determined from a combination of various AGN samples.Both of the BHMF and ERDF are modeled with an exponential-cutoff, the high luminosity end of the luminosity function cannot be reproduced.

SXDS AGNs at z=1-2

For black hole mass function, we limit the sample within the redshift range between 1.18<z<1.68. There areBroad-line AGN : with zspec 118 objects, zphot only 10 objectsNarrow-line AGN : with zspec 66 objects, zphot only 92 objects, NO MBH with Broad-line FWHM

Contribution of obscured narrow-line AGNs

Among the X-ray-selected AGNs in the redshift range, more than half of the AGNs are obscured narrow-line AGNs. The contribution of these obscured narrow-line AGNs to the active binned BHMF is evaluated using the hard-band sample.BH f b d li AGN i d iBH mass of obscured narrow-line AGNs are estimated assuming constant Eddington ratio for each luminosity range.

Contribution of obscured narrow-line AGNs

Hard-band sample

Black hole mass function for 2-10keV selected sample.Open circles: BHMF for broad-line AGNs onlyOpen triangles: BHMF including contribution of obscured narrow-line AGNs.Th lid d d d d h d li i BHMF 0 1 2 f K b dThe solid, dotted, and dashed lines are non-active BHMF at z=0, 1, 2 from K-band LF of galaxies (Li et al. 2011).

Summary for Nobuta et al. 2012• z~1.4 active BH mass function shows peak at 10^8.5 Msolar, and has a higher number density above 10^8 Msoloar but a lower number density below that mass

h h i h l l U i Th l irange than that in the local Universe. The evolution may be indicative of a down-sizing trend of accretion activity among the SMBH population.

• The evolution of ERDF from z=1.4 to z=0 indicates that the fraction of AGNs with accretion rate close to the Eddington limit is higher at higher redshiftsEddington-limit is higher at higher redshifts.

• Both evolutions of the BHMF and ERDF drive the observed evolution of the LF from z=1 4 to z=0observed evolution of the LF from z=1.4 to z=0.

• In order to explain the double power-law shape of the AGN LF, either BHMF or ERDF needs to be extended toAGN LF, either BHMF or ERDF needs to be extended to higher BH mass or larger ER.

• If contribution from obscured AGNs considered, the co t but o o obscu ed G s co s de ed, t efraction of active BH among entire SMBHs should be fairly high at z~1.4 (order of ~10%).

Intrinsic BHMF and ERDF

• The estimated BHMF and ERDF so far are not corrected for the tt i th MBH ti tscatter in the MBH estimate.

• “Signle-epoch” MBH estimate can have 0.4-0.5 dex scatter.

Intrinsic BHMF and ERDF at z~1.4

If we consider the effect of the scatter of the MBH estimate;Black lines: Fitting w/o scatter of the MBH estimateBlack lines: Fitting w/o scatter of the MBH estimateBlue lines: Fitting with scatter of the MBH estimate (half)Green lines: Fitting with scatter of the MBH estimate (full)

Estimation of Intrinsic BHMF and ERDF, possible degeneracypossible degeneracy

The estimation of the intrinsic BHMF and ERDF can have degeneracy.

Future

• Examine evolution of the BHMF and ERDF in the X-ray-selected sample by

E t di th t d t id d hift ( 1 18 1 68• Extending the study to wider redshift range (z=1.18-1.68 -> z=0.9-2.0) with broad MgII line observations in redder wavelength range (>8000A).

• Intrinsic BHMF and ERDF with obscured AGNs (~ maximum likelihood estimation with obscured AGNs without broad-line measurements).

• Understand populations of AGNs which are missed in the X-rayUnderstand populations of AGNs which are missed in the X ray surveys

• Heavily-obscured Compton-thick AGNs.• Narrow line Seyfert 1s with very soft X ray spectrum• Narrow-line Seyfert 1s with very soft X-ray spectrum.

• Subaru Prime-Focus Spectrograph !

• TMT in the early universe !

Thank you for your attentionThank you for your attention.

Future• TMT for the BH statistics in the early universe !TMT for the BH statistics in the early universe !

Deepest X-ray image by ChandraDeepest NIR image by Subaru

+ Optical image by HSTp y g y + Optical image by HST

Evolution of Broad-line AGN BH Mass Functions from SDSS

Shen & Kelly 2012(Kelly et al. 2009, 2010)y

SDSS sample only covers most massive BHs with high-Eddington (~1) ratio. In order to understand the AGNs dominating accretion growth of SMBHs itIn order to understand the AGNs dominating accretion growth of SMBHs, it is necessary to reveal fainter AGNs (~knee of X-ray logN-logS).

Active BHMF at z~1.4 compared with SDSS resultsp

SXDS 1 18 1 68SXDS 1.18 < z <1.68

Z=1.4SDSS DR7 (Shen & Kelly 2012)

Circles: binned estimates with VmaxCircles: binned estimates with VmaxSolid lines: esimated with Bayesian method

ERDF at z~1.4 Compared with SDSS

SXDS 8 68SXDS 1.18 < z <1.68

Blue lines:SDSS DR7 (Shen & Kelly 2012)

Eddington Ratio Distribution Function

We compare the binned ERDFs in the two mass ranges 10^8.0-8.5 M l (bl ) d 10^8 5 9 0M l ( d) N i ifi diffMsoloar (blue) and 10^8.5-9.0 Msoloar (red). No significant difference observed within the uncertainty.

Active BHMF at z~1.4 compared with SDSS resultsp

SXDS 1 18 1 68SXDS 1.18 < z <1.68

Z=1.4SDSS DR7 (Shen & Kelly 2012)SDSS DR7 (Shen & Kelly 2012)

Circles: binned estimates with VmaxSolid lines: esimated with Bayesian method