Evolution of the AGN Population in the Universe

170 Pages·2017·21.49 MB·English

ETH Library
Evolution of the AGN Population in
the Universe
Doctoral Thesis
Author(s):
Caplar, Neven
Publication date:
2017
Permanent link:
https://doi.org/10.3929/ethz-b-000200655
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In Copyright - Non-Commercial Use Permitted
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DISS. ETH NO. 24552
EVOLUTION OF THE AGN
POPULATION IN THE
UNIVERSE
A thesis submitted to attain the degree of
DOCTOR OF SCIENCES of ETH ZURICH
(Dr. sc. ETH Zurich)
presented by
Neven Cˇaplar
mag. phys., University of Zagreb
born on October 10th, 1986
citizen of Republic of Croatia
accepted on the recommendation of
Prof. Dr. Simon J. Lilly, examiner
Prof. Dr. Paul C. Hewett, co-examiner
2017
Contents
List of Figures vii
List of Tables ix
Abstract xi
Kurzfassung xiii
1 Introduction 1
1.1 Active galactic nuclei . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1.1 AGN components and accretion. . . . . . . . . . . . . . . . . . . . . 1
1.1.2 AGN luminosity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1.3 Measurement of black hole masses . . . . . . . . . . . . . . . . . . . 4
1.2 Galaxy population . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.2.1 Two galaxy populations . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.2.2 Phenomenologicalapproachtodescribeevolutionofgalaxypopulation 8
1.3 Co-evolution of black holes and their host galaxies . . . . . . . . . . . . . . 10
1.3.1 Cosmic density of mass accretion of black holes and galaxies . . . . 11
1.3.2 Black hole-galaxy correlations . . . . . . . . . . . . . . . . . . . . . 11
1.3.3 Evolution of the galaxy-black hole mass relations . . . . . . . . . . . 13
1.4 Variability of AGN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
1.5 Organization and content of this thesis . . . . . . . . . . . . . . . . . . . . . 17
2 AGN and galaxies: co-existence scenario 19
2.1 Ans¨atze . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.2 The origin of the quasar luminosity function . . . . . . . . . . . . . . . . . . 20
2.2.1 Convolution of Schechter functions with power law Eddington ratios 20
2.2.2 ThesimplestEddingtonratiodistributionthatreproducestheshape
of the QLF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
2.2.3 BrokenpowerlawEddingtonratiodistributionandgeneralizedduty
cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
2.2.4 Analytical derivation of the QLF . . . . . . . . . . . . . . . . . . . 25
2.2.5 Predictions of the convolution model . . . . . . . . . . . . . . . . . . 28
2.3 Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
2.3.1 Mass function of star-forming galaxies . . . . . . . . . . . . . . . . . 31
2.3.2 Quasar luminosity function . . . . . . . . . . . . . . . . . . . . . . . 33
iii
CONTENTS
2.4 Results from comparing the evolution of the QLF and the galaxy mass
function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
2.4.1 The evolution of QLF normalization . . . . . . . . . . . . . . . . . . 35
2.4.2 The evolution of characteristic QLF luminosity . . . . . . . . . . . . 37
2.5 Testing the model with black hole mass data . . . . . . . . . . . . . . . . . 39
2.5.1 The quasar mass-luminosity plane . . . . . . . . . . . . . . . . . . . 39
2.5.2 Establishing the m /m correlation in quenched systems . . . . . . 43
bh ∗
2.5.3 The m /m correlation in quenched systems . . . . . . . . . . . 46
bh bulge
2.5.4 Quenched galaxies as a function of galaxy and black hole mass . . . 48
2.5.5 m /m in AGN in the local Universe . . . . . . . . . . . . . . . . . 50
bh ∗
2.6 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
2.6.1 Comparing m /m redshift evolution in active and quenched systems 52
bh ∗
2.6.2 Downsizing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
2.7 Connection of the shape of Eddington distribution and mass ratio evolution 55
2.7.1 Coherent evolution of φ∗ and φ∗ . . . . . . . . . . . . . . . . . . 56
SF QLF
2.8 Summary and conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
3 AGN and galaxies: quenching scenario 61
3.1 Is the mass ratio evolution consistent with the observed mass growth in the
universe? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
3.1.1 Mass growth of star-forming galaxies at low redshifts (z (cid:46) 0.7) . . . 62
3.1.2 Mass growth of star-forming galaxies and black holes in co-existence
scenario . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
3.2 New convolution scenario . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
3.2.1 Qualitative explanation of the quenching scenario . . . . . . . . . . . 64
3.2.2 Predictions for the mass function of AGN and AGN host galaxies . 66
3.2.3 Connection between mass accretion and the mass function of galax-
ies and AGN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
3.3 Observational determination of parameters describing AGN mass function
and Eddington ratio function . . . . . . . . . . . . . . . . . . . . . . . . . . 71
3.4 Quantitative discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
3.4.1 Description of the calculation . . . . . . . . . . . . . . . . . . . . . . 75
3.4.2 Predictions of the quenching scenario and comparison with the con-
clusions from the co-existence scenario . . . . . . . . . . . . . . . . 77
3.5 Summary and conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
4 Differentiating between AGN-galaxy co-evolution scenarios 81
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
4.2 Galaxy properties as a function of AGN luminosity . . . . . . . . . . . . . . 82
4.3 AGN properties as a function of galaxy mass . . . . . . . . . . . . . . . . . 84
4.4 Summary and conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
5 Optical variability 93
5.1 The sample & data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
5.2 Re-calibration of the PTF AGN Light Curves . . . . . . . . . . . . . . . . . 96
5.3 Analysis Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
iv
CONTENTS
5.3.1 Construction of the structure functions . . . . . . . . . . . . . . . . 98
5.3.2 Wavelength correction . . . . . . . . . . . . . . . . . . . . . . . . . . 101
5.3.3 Fitting the structure function . . . . . . . . . . . . . . . . . . . . . . 102
5.3.4 Construction and testing of PSDs. . . . . . . . . . . . . . . . . . . . 105
5.4 Results of the SF analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
5.4.1 The amplitude and the timescale of variability from the SF analysis 110
5.5 Results of the PSD analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
5.5.1 Slope of PSDs in the (i)PTF sample . . . . . . . . . . . . . . . . . . 116
5.6 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
5.7 Summary and conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
6 Summary and future prospects 125
6.1 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
6.2 Future prospects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
6.2.1 InfluenceofsteepPSDslopeondetectionofperiodicAGNlightcurves130
6.2.2 Variabilityasamethodtomeasurespinandotherphysicalparameters130
6.2.3 Variability as AGN selection method . . . . . . . . . . . . . . . . . . 131
Appendix to Chapter 5 133
A.1 Completeness and depth of the survey . . . . . . . . . . . . . . . . . . . . . 133
A.2 Comparison of calibration with Ofek et al. (2012) . . . . . . . . . . . . . . . 134
A.3 Colour dependence of the calibration . . . . . . . . . . . . . . . . . . . . . . 135
A.4 Reduction of SF2 residuals using the stellar sample . . . . . . . . . . . . . 136
Bibliography 139
Acknowledgements 152
v
CONTENTS
vi
List of Figures
1.1 Schematic illustration of AGN . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2 Main Sequence of star-formation . . . . . . . . . . . . . . . . . . . . . . . . 8
1.3 The red fraction in SDSS as function of stellar mass and environment . . . 10
1.4 Cosmic evolution of the star formation rate density and the black hole
accretion rate density . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1.5 Correlation between masses of black holes and galaxy bulges . . . . . . . . 13
2.1 Schematic representation of the procedure to create the QLF . . . . . . . . 21
2.2 Functional dependence of the factors ∆ (δ ,γ ) and ∆ (δ ,γ ) . . . . . . . 26
L 1 2 φ 1 2
2.3 Comparison of the shape of the QLF and the result of the convolution . . . 27
2.4 Shape of black hole and black hole host functions . . . . . . . . . . . . . . . 28
2.5 Evolution of parameters describing mass function of star-forming galaxies . 31
2.6 Fits of the results of the model to the QLF . . . . . . . . . . . . . . . . . . 34
2.7 Redshift evolution of parameters describing QLF; “full fit”. . . . . . . . . . 35
2.8 Redshift evolution of parameters describing QLF; normalization evolution
fixed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
2.9 Comparison of the redshift evolution of the normalization of star-forming
galaxy mass function and the normalization of quasar luminosity function . 38
2.10 Mass - luminosity plane; comparison with observations . . . . . . . . . . . . 40
2.11 Mass - luminosity plane, without luminosity cuts . . . . . . . . . . . . . . . 43
2.12 m /m relation in quenched galaxies today . . . . . . . . . . . . . . . . . . 44
bh ∗
2.13 Correlation of black hole mass with total and bulge mass in quenched galaxies 47
2.14 Scatter in the black hole - galaxy relation . . . . . . . . . . . . . . . . . . . 48
2.15 Quenched fraction as a function of stellar and black hole mass . . . . . . . . 49
2.16 Simulated observation of m /m relation in Stripe 82 . . . . . . . . . . . . 51
bh ∗
2.17 Evolution of the mean m /m relation in star-forming and quenched systems 53
bh ∗
2.18 Redshift evolution of comoving density of quasars at different luminosities . 54
2.19 Evolution of the high-end slope of Eddington distribution . . . . . . . . . . 55
3.1 Maximal evolution of the m /m relation in a star-forming galaxy on the
bh ∗
Main Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
3.2 Schematic representation of the model in which AGN are connected with
mass quenching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
3.3 Mass function of AGN and AGN host galaxies in the quenching scenario . . 67
3.4 Redshift evolution of BHARD and SFRD . . . . . . . . . . . . . . . . . . . 73
3.5 Redshift evolution of BHARD/SFRD . . . . . . . . . . . . . . . . . . . . . . 74
3.6 Redshift evolution of (SFRD/BHARD) (L∗/M∗) . . . . . . . . . . . . . . 75
·
vii
LIST OF FIGURES
3.7 Mass - luminosity plane in quenching scenario; comparison with observations 78
3.8 m /m relation in quenched galaxies today; quenching scenario . . . . . . 79
bh ∗
4.1 Star formation as a function of AGN luminosity I. . . . . . . . . . . . . . . 83
4.2 Star formation as a function of AGN luminosity II. . . . . . . . . . . . . . 84
4.3 Effect of small field of view on the observational results . . . . . . . . . . . 86
4.4 BHAR/SFR as a function of stellar mass of star-forming galaxies at z 2 . 88
∼
4.5 BHAR/SFR as a function of stellar mass of star-forming galaxies at z 1.. 89
∼
5.1 Distribution of observational cadence in the sample . . . . . . . . . . . . . . 94
5.2 Cumulative distribution of the number of observations for the objects in
the sample . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
5.3 Cumulative distribution of the time span of the observations for the objects
in the sample . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
5.4 SF2 split by redshift, luminosity and mass . . . . . . . . . . . . . . . . . . . 100
5.5 Variability as a function of wavelength . . . . . . . . . . . . . . . . . . . . . 102
5.6 Examples of PSD for four representative light curves . . . . . . . . . . . . . 106
5.7 Result of the simulations to test accuracy of PSD estimation . . . . . . . . 108
5.8 Result of the simulations to test accuracy of PSD estimation; fraction of
steep slopes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
5.9 Value of the log(SF/mag) at a time scale of 100 days . . . . . . . . . . . . . 110
5.10 The dependence of the SF2 as a function of the luminosity L. . . . . . . . . 111
5.11 Time-scale at which the ensemble structure function reaches 0.071 mag. . . 112
5.12 The dependence of the SF2 as a function of the luminosity relative to the
knee of the quasar luminosity function at that redshift . . . . . . . . . . . . 115
5.13 The dependence of the PSD slope, α, with mass and luminosity . . . . . . . 117
5.14 The dependence of the PSD slope, α, with mass and luminosity for the
SDSS Stripe 82 data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
5.15 The short time-scale slopes of the structure function SF2 as a function of
luminosity and mass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
5.16 Simple model for the observed steepening of PSD slopes with mass in the
observations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
6.1 Periodicity in surveys as function of PSD slope . . . . . . . . . . . . . . . . 131
A.1 The completeness of the survey as a function of the observed magnitude of
the source and the dimming of the observation . . . . . . . . . . . . . . . . 134
A.2 Comparison of the results for the quasar SF2 using the standard (i)PTF
calibration and our re-calibration . . . . . . . . . . . . . . . . . . . . . . . . 135
A.3 Example of the light-curve using our re-calibration and using the standard
(i)PTF calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
A.4 The SF2 for stars (averaged over all ∆t) as a function of their colour . . . . 137
A.5 Schematic representation of our procedure to create the final SF2 estimate
for a quasar sample . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
viii
List of Tables
2.1 Evolution of star-forming galaxy mass function, data from Ilbert et al. (2013) 32
2.2 Best fits to QLF data from Hopkins et al. (2007) . . . . . . . . . . . . . . . 34
5.1 Fit of SF2 with Equation (5.4), table of parameters . . . . . . . . . . . . . 104
5.1 Fit of SF2 with Equation (5.4), table of parameters . . . . . . . . . . . . . 105
5.2 Fit to the time-scale of variability, Equation (5.7) . . . . . . . . . . . . . . 113
5.3 Dependence of the SF2 slope, fit with Equation (5.14) . . . . . . . . . . . . 120
ix
LIST OF TABLES
x