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A Multiscale View of Active Galactic Nuclei Jets: from the Formation and Acceleration to High Energy Outbursts
| DC Field | Value | Language |
|---|---|---|
| dc.contributor.advisor | Sascha Trippe | - |
| dc.contributor.author | 박종호 | - |
| dc.date.accessioned | 2019-10-21T03:40:27Z | - |
| dc.date.available | 2019-10-21T03:40:27Z | - |
| dc.date.issued | 2019-08 | - |
| dc.identifier.other | 000000157150 | - |
| dc.identifier.uri | https://hdl.handle.net/10371/162433 | - |
| dc.identifier.uri | http://dcollection.snu.ac.kr/common/orgView/000000157150 | ko_KR |
| dc.description | 학위논문(박사)--서울대학교 대학원 :자연과학대학 천문학과,2019. 8. Sascha Trippe. | - |
| dc.description.abstract | Active Galactic Nuclei (AGNs) often produce highly collimated relativistic jets, one of the most energetic phenomena in the Universe. In this thesis, we probe the mechanism of launching, propagation, and energy dissipation of AGN jets by using various methodologies. We study the jet of a nearby radio galaxy M87 with very long baseline interferometry observations and find that the jet is collimated by the pressure of non-relativistic winds launched from hot accretion flows and accelerated to relativistic speeds by strong magnetic fields in the jet. We investigate the frequency dependence of Faraday rotation of many AGN jets and reveal that recollimation shocks in the jets may play an important role in dissipation of the jet kinetic energy. We examine the association of strong γ-ray flares occurred in 2015 in the jet of PKS 1510–089 and its peculiar kinematic behavior and find that the flares may originate from compression of the jet knots by a standing shock in the core. We study the long-term radio variability of many radio-loud AGNs by employing temporal Fourier transform of the light curves and reveal that the radio variability can be controlled by the accretion processes. We constrain the properties of the radio-emitting source known as Sagittarius A*, which is potentially powered by jets, by a very long baseline interferometry observation during the passage of the gas cloud G2 through the vicinity of the supermassive black hole. | - |
| dc.description.tableofcontents | Abstract
List of Figures List of Tables 1. Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 Jets in Active Galactic Nuclei . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1.1 Phenomenology . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1.2 How are AGN jets produced? . . . . . . . . . . . . . . . . . . . 10 1.1.3 Accretion flows and winds . . . . . . . . . . . . . . . . . . . . . . 19 1.1.4 Recollimation shocks and energy dissipation . . . . . . . . . . . . 27 1.1.5 M87: the best target for AGN jet astrophysics . . . . . . . . . . 37 1.2 The gas cloud G2 passing through the vicinity of Sagittarius A* . . . . 42 1.3 Very Long Baseline Interferometry . . . . . . . . . . . . . . . . . . . . . 44 1.4 Power spectrum of light curve . . . . . . . . . . . . . . . . . . . . . . . . 49 1.5 Thesis outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 2. Faraday Rotation in the Jet of M87 inside the Bondi Radius: Indication of Winds from Hot Accretion Flows Confining the Relativistic Jet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 2.2 Archival data and data reduction . . . . . . . . . . . . . . . . . . . . . . 60 2.3 Analysis and Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 2.3.1 RM maps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 2.3.2 Radial RM profile . . . . . . . . . . . . . . . . . . . . . . . . . . 66 2.3.3 Contribution of RM sources outside the Bondi radius . . . . . . 69 2.3.4 Variability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 2.3.5 The Faraday screen . . . . . . . . . . . . . . . . . . . . . . . . . 71 2.4 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 2.4.1 Jet sheath vs hot accretion flows . . . . . . . . . . . . . . . . . . 81 2.4.2 Winds and the Faraday screen . . . . . . . . . . . . . . . . . . . 84 2.4.3 Jet collimation by winds . . . . . . . . . . . . . . . . . . . . . . . 85 2.4.4 Mis-alignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 2.4.5 Mass accretion rate . . . . . . . . . . . . . . . . . . . . . . . . . . 88 2.4.6 RM at HST-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 2.4.7 EHT observations . . . . . . . . . . . . . . . . . . . . . . . . . . 92 2.5 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 3 Intensive Monitoring of the M87 Jet with KaVA: Jet Kinematics based on Observations in 2016 at 22 and 43 GHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 3.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 3.2 Observations and Data Reduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 3.3 Summary of Previous Studies of the M87 Jet Kinematics . . . . . . . . . 104 3.4 Jet Kinematics on Scales of . 20 mas Based on KaVA Observations . . 108 3.4.1 Modelfit with Circular Gaussian Components . . . . . . . . . . . 108 3.4.2 Modelfit with Point Sources and Grouping . . . . . . . . . . . . . 112 3.4.3 Wise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 3.4.4 Jet Apparent Speeds and Comparison with Other Studies . . . . 119 3.5 Jet Kinematics on Scales of ≈ 340 − 410 mas Based on VLBA Archive Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120 3.6 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126 3.6.1 Slow Jet Acceleration . . . . . . . . . . . . . . . . . . . . . . . . 128 3.6.2 Multiple Streamlines and Velocity Stratification . . . . . . . . . . 132 3.6.3 Current Limitations and Future Prospects . . . . . . . . . . . . . 133 3.7 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 4 Revealing the Nature of Blazar Radio Cores through Multi-Frequency Polarization Observations with the Korean VLBI Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137 4.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138 4.2 Observations and Data Reduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142 4.3 results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147 4.3.1 RM at radio wavelengths . . . . . . . . . . . . . . . . . . . . . . 147 4.3.2 Optical EVPAs from the Steward observatory . . . . . . . . . . . 163 4.3.3 fractional polarization . . . . . . . . . . . . . . . . . . . . . . . . 168 4.4 discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170 4.4.1 RM distributions at different frequencies . . . . . . . . . . . . . . 170 4.4.2 Change of core opacities from optically thick to thin . . . . . . . 173 4.4.3 The Faraday screen. . . . . . . . . . . . . . . . . . . . . . . . . 174 4.4.4 RM sign change. . . . . . . . . . . . . . . . . . . . . . . . . . . 175 4.4.5 Optical subclasses . . . . . . . . . . . . . . . . . . . . . . . . . . 177 4.4.6 Intrinsic polarization orientation . . . . . . . . . . . . . . . . . . 178 4.4.7 Multiple recollimation shocks in the cores . . . . . . . . . . . . . 179 4.5Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181 5 Ejection of Double knots from the radio core of PKS 1510–089 during the strong γ-ray flares in 2015. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185 5.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186 5.2 Multi-wavelength Light Curves . . . . . . . . . . . . . . . . . . . . . . . 190 5.2.1 iMOGABA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190 5.2.2 SMA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192 5.2.3 Radio Spectral Index . . . . . . . . . . . . . . . . . . . . . . . . . 192 5.2.4 Optical Photometric Data . . . . . . . . . . . . . . . . . . . . . . 193 5.2.5 Fermi-LAT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193 5.3 Jet kinematics and linear polarization analysis . . . . . . . . . . . . . . 194 5.4 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200 5.4.1 Comparison of the γ-ray flares in 2015 with previous flares . . . 200 5.4.2 Double-knot Jet Structure . . . . . . . . . . . . . . . . . . . . . . 201 5.4.3 Acceleration motions and Spine-sheath Scenario . . . . . . . . . 204 5.4.4 Origin of the 2015 γ-ray flare . . . . . . . . . . . . . . . . . . . . 207 5.5 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209 6 Radio Variability and Random Walk Noise Properties of Four Blazars. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211 6.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212 6.2 Target Selection and Flux Data . . . . . . . . . . . . . . . . . . . . . . . 214 6.3 Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215 6.3.1 Lightcurves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215 6.3.2 Spectral indices. . . . . . . . . . . . . . . . . . . . . . . . . . . 215 6.3.3 Time offsets among spectral bands . . . . . . . . . . . . . . . . . 217 6.3.4 Periodograms. . . . . . . . . . . . . . . . . . . . . . . . . . . . 220 6.3.5 Simulated lightcurves and significance levels. . . . . . . . . . . 222 6.4 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224 6.4.1 3C 279 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224 6.4.2 3C 345 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225 6.4.3 3C 446 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225 6.4.4 BL Lac . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226 6.5 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226 6.5.1 Spectral indices . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226 6.5.2 Spectral time delays . . . . . . . . . . . . . . . . . . . . . . . . . 227 6.5.3 Power spectra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228 6.6 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229 7 The long-term centimeter variability of active galactic nuclei: A new relation between variability timescale and accretion rate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231 7.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232 7.2 Sample and Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236 7.3 Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240 7.3.1 Lightcurves and Power Spectra . . . . . . . . . . . . . . . . . . . 240 7.3.2 Fractal Dimension . . . . . . . . . . . . . . . . . . . . . . . . . . 243 7.3.3 Fitting Lightcurves Piecewise with Gaussian Peaks . . . . . . . . 248 7.3.4 Derivatives of Lightcurves . . . . . . . . . . . . . . . . . . . . . . 250 7.3.5 Black Hole Masses and Accretion Rates . . . . . . . . . . . . . . 250 7.4 Results and Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254 7.4.1 General Features of Power Spectra . . . . . . . . . . . . . . . . . 254 7.4.2 Distributions of Fractal Dimension . . . . . . . . . . . . . . . . . 256 7.4.3 β as an Indicator of Variability Timescale . . . . . . . . . . . . . 257 7.4.4 Relation between β and the Accretion Rate . . . . . . . . . . . . 262 7.4.5 Broken Power-law Periodograms . . . . . . . . . . . . . . . . . . 274 7.4.6 Comparison with Other Studies . . . . . . . . . . . . . . . . . . . 282 7.5 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286 8 No asymmetric outflows from Sagittarius A* during the pericenter passage of the gas cloud G2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293 8.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294 8.2 Observations and data analysis . . . . . . . . . . . . . . . . . . . . . . . 296 8.3 Discussion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299 Bibliography. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305 Appendix. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338 A Appendices for Chapter 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 339 A.1 Errors in linear polarization quantities . . . . . . . . . . . . . . . . . . . 339 A.2 Significance level of RM . . . . . . . . . . . . . . . . . . . . . . . . . . . 343 A.3 RM maps for all observations . . . . . . . . . . . . . . . . . . . . . . . . 346 A.4 Radial RM profiles for the northern and southern jet edges . . . . . . . 348 B Appendices for Chapter 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349 B.1 WISE Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349 C Appendices for Chapter 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353 C.1 D-Term calibration and evolution. . . . . . . . . . . . . . . . . . . . . 353 C.2 Reliability check of KVN polarimetry. . . . . . . . . . . . . . . . . . . 358 Conclusion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363 요 약. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369 | - |
| dc.language.iso | eng | - |
| dc.publisher | 서울대학교 대학원 | - |
| dc.subject | galaxies: active | - |
| dc.subject | galaxies: jets | - |
| dc.subject | relativistic processes | - |
| dc.subject | radiation mechanisms | - |
| dc.subject | non-thermal | - |
| dc.subject | polarization | - |
| dc.subject | accretion | - |
| dc.subject | accretion disks | - |
| dc.subject | techniques: interferometric | - |
| dc.subject.ddc | 520 | - |
| dc.title | A Multiscale View of Active Galactic Nuclei Jets: from the Formation and Acceleration to High Energy Outbursts | - |
| dc.type | Thesis | - |
| dc.type | Dissertation | - |
| dc.contributor.department | 자연과학대학 천문학과 | - |
| dc.description.degree | Doctor | - |
| dc.date.awarded | 2019-08 | - |
| dc.identifier.uci | I804:11032-000000157150 | - |
| dc.identifier.holdings | 000000000040▲000000000041▲000000157150▲ | - |
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