Mean and Extreme Radio Properties of Quasars and the Origin of Radio Emission A Thesis Submitted to the Faculty of Drexel University by Rachael Marie Kratzer in partial fulfillment of the requirements for the degree of Doctor of Philosophy June 2014 c Copyright 2014 Rachael Marie Kratzer. All Rights Reserved ii Dedications To Louie, my dedicated companion since 2004 iii Acknowledgments First and foremost, I thank my thesis adviser, Gordon Richards, for his guidance and limitless patience over the past seven years. I am truly grateful for the opportunities he has made possible. Without his support, this thesis would certainly not exist. I am indebted to David Goldberg for his dedicated mentorship, which extended beyond academia to life, in general. I thank Rick White for providing the FIRST completeness calculations, his object stacking code, and his radio expertise. I am grateful to my remaining committee members, Michael Vogeley and Brigita Urbanc, for their useful feedback and encouragement throughout the development of this research. I thank my colleagues for comments on the manuscript, particularly Bob Becker and Amy Kimball. I also acknowledge Adam Myers for help constructing the Master quasar catalog and Coleman Krawczyk for providing corrected black hole masses for my samples. This work was supported by NSF AAG grant 1108798. Funding for the SDSS and SDSS-II was provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, the U.S. Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, the Max Planck Society, and the Higher Education Funding Council for England. The SDSS was managed by the Astrophysical Research Consortium for the Partic- ipating Institutions. Funding for SDSS-III has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, and the U.S. Department of Energy Office of Science. The SDSS-III web site is http://www.sdss3.org/. SDSS-III is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS-III Collaboration including the University of Arizona, the Brazilian Participation Group, Brookhaven National Labo- ratory, Carnegie Mellon University, University of Florida, the French Participation Group, the Ger- man Participation Group, Harvard University, the Instituto de Astrofisica de Canarias, the Michigan State/Notre Dame/JINA Participation Group, Johns Hopkins University, Lawrence Berkeley Na- tional Laboratory, Max Planck Institute for Astrophysics, Max Planck Institute for Extraterrestrial iv Physics, New Mexico State University, New York University, Ohio State University, Pennsylvania State University, University of Portsmouth, Princeton University, the Spanish Participation Group, University of Tokyo, University of Utah, Vanderbilt University, University of Virginia, University of Washington, and Yale University. v Table of Contents List of Figures .......................................... vii Abstract .............................................. xi 1. History of Quasars ...................................... 1 2. Commentary on the Radio-Loud Bimodality ...................... 5 3. Data ............................................... 9 3.1 Sloan Digital Sky Survey................................... 9 3.2 FIRST............................................. 10 3.3 DR7 Quasar Catalog..................................... 11 3.4 Master Quasar Catalog.................................... 12 3.5 My Samples.......................................... 13 3.6 Diagnostics .......................................... 14 3.6.1 Optical Luminosity and Redshift ............................ 15 3.6.2 Radio-Loudness...................................... 16 3.6.3 Radio Luminosity..................................... 19 3.6.4 Extended Flux Underestimation............................. 21 3.6.5 FIRST Detection Limit ................................. 22 3.7 Radio Loud Definition.................................... 24 4. Radio Properties in the Extreme: the Radio-Loud Fraction (RLF) . 27 4.1 The RLF as a function of L and z ............................. 27 4.2 The RLF and Accretion Disk Winds: Principal Component and CIV Analyses . 30 4.3 The RLF and Black Hole Mass............................... 34 5. Radio Properties in the Mean: Stacking Analysis . 39 5.1 Motivation .......................................... 39 5.2 Image Stacking........................................ 39 vi 5.3 Median Stacking Diagnostics ................................ 40 5.4 The Mean Radio Properties as a Function of L and z ................... 42 5.5 Radio-Optical Spectral Index as a Function of Luminosity................ 46 5.6 The Mean Radio Properties and Accretion Disk Winds: Principal Component and CIV Analyses............................................ 51 5.7 The Mean Radio Properties and Black Hole Mass..................... 53 5.8 The Mean Radio Properties as a Function of Color.................... 54 6. Discussion ............................................ 58 6.1 Luminosity and Redshift Evolution............................. 58 6.2 Mass, Accretion Rate, and Spin............................... 59 6.3 Accretion Disk Winds .................................... 62 6.4 On the Meaning of Radio-Quiet............................... 63 7. Conclusions ........................................... 65 Bibliography ............................................ 67 Vita .................................................. 78 vii List of Figures 3.1 Histograms of the redshift distribution for Sample A (left; yellow), Sample B (left; green), Sample C (right; blue), and Sample D (right; purple). Note that the two plots use different y-axis scalings. Sample C fills in the redshift distribution gap seen near z ∼ 2:7 in Samples A and B, while Sample D vastly increases the sample size by probing deeper than the spectroscopic samples (A,B,C) at the expense of the redshift distribution (and redshift accuracy)........................................ 15 3.2 Histograms of the i-band magnitude distribution for all four samples (colors are as out- lined in Fig. 3.1). Again, note that the two plots use different y-axis scalings. The distribution of Sample A (left; yellow) reflects the different limiting magnitudes for z < 3 and z > 3 quasar selections in SDSS. Sample C (right; blue) demonstrates the extension to fainter magnitudes by the SDSS-III BOSS quasars, while Sample D (right; purple) probes even fainter objects (while eliminating brighter objects where the efficiency of photometric quasar selection is lower due to higher stellar density)............. 16 3.3 L K-corrected to z = 2 as a function of redshift. The cuts made to Sample A 2500 A˚ (yellow) to create Sample B (green) are evident as the removal of the faintest sources with z < 3. After making cuts to Sample D (purple) to create a relatively uniform subsample, photometric redshift degeneracies manifest themselves as bands of missing objects. ............................................. 17 3.4 Radio magnitude (t) of detected FIRST sources as a function of i. The dashed diagonal lines represent different values of the radio-loudness parameter, log R, with the boundary between RL and RQ, log R = 1, highlighted in red. It is apparent for all four samples that the radio flux limit significantly restricts the distribution of log R to predominately RL values (for radio detected sources)............................. 18 3.5 Radio-loudness, log R, as a function of i for optically confirmed quasars within the FIRST observing area. Quasars undetected by FIRST are assigned a flux of 1 mJy to calculate log R. Quasars undetected by FIRST at i < 18:9 can be considered as RQ, but fainter objects can still be RL despite being undetected by FIRST................. 19 3.6 Radio luminosity as a function of redshift for optically confirmed quasars within the FIRST observing area. Quasars undetected by FIRST are assigned a flux of 1 mJy to calculate Lrad. The horizontal dashed gray line denotes a division between RL and RQ quasars employed by Jiang et al.(2007). It is evident that high-redshift quasars ( z ∼> 3:5) can simultaneously be intrinsically radio-loud and FIRST non-detections. Alternatively, FIRST non-detections for lower redshifts (z ∼< 3:5) strongly indicate that an object is RQ. 21 3.7 Source size, indicated by the ratio of the integrated to peak fluxes (θ), as a function of redshift for FIRST-detected quasars.............................. 22 3.8 FIRST completeness (provided by R. L. White 2013, private communication) as a func- tion of integrated radio flux (mJy)............................... 23 viii 3.9 Spectral energy diagram comparing the distribution of power in the radio, optical, and X-ray regimes. The black lines show the mean radio-to-UV-to-X-ray SED of a quasar −1 −1 with L equal to 30 ergs s Hz . αro and αox give the slope of the SED between 2500 A˚ the radio and optical and the optical and X-ray. αro is not universal for quasars; here I have shown the slope corresponding to the traditional division between RL (steeper slopes) and RQ (flatter slopes). The red and blue lines show the range of radio slopes in that part of the SED. The solid and dashed gray curves show the mean RQ and mean RL SEDs, respectively, from Elvis et al.(1994). The dotted gray line shows a slope equivalent to log R = 3|particularly radio-loud. At the bottom of the panel I show the transmission of the 1.4GHz and i-band bandpasses at z = 0, 2, and 4 (as black, dark gray, and