Astrophysical Plasma Modeling of the Hot Universe
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Astrophysical plasma modeling of the hot Universe Advances and challenges in high-resolution X-ray spectroscopy Astrophysical plasma modeling of the hot Universe Advances and challenges in high-resolution X-ray spectroscopy Proefschrift ter verkrijging van de graad van Doctor aan de Universiteit Leiden, op gezag van de Rector Magnificus prof. mr. C. J. J. M. Stolker, volgens besluit van het College voor Promoties te verdedigen op donderdag 7 juni 2018 klokke 10:00 uur door Junjie Mao geboren te Ningbo, China in 1988 Promotiecommissie: Promotor: Prof. dr. J. S. Kaastra Co-promotor: Dr. J. de Plaa (SRON) Overige leden: Prof. dr. H. Röttgering Prof. dr. J. Schaye Prof. dr. W. R. Jaffe Prof. dr. G. Branduardi-Raymont (University College London) Prof. dr. F. B. S. Paerels (Columbia University) To Lilan our active family nucleus with her inflows and outflows © 2018 Junjie Mao Cover design by Junjie Mao Image credit: Adobe Spark Contents 1 Introduction 1 1.1 Hot astrophysical plasmas in X-rays . 2 1.2 Active Galactic Nuclei and circumnuclear media . 3 1.3 Intracluster media and chemical enrichment . 9 1.4 Plasma code and atomic data . 13 1.5 This thesis . 15 References. 18 2 Parameterization of the level-resolved radiative recombination rate coefficients for the SPEX code 21 2.1 Introduction . 22 2.2 Historical background . 22 2.3 RR rate coefficients for H-like ions . 25 2.3.1 Photoionization cross sections . 25 2.3.2 Radiative recombination data . 26 2.4 RR rate coefficients for He-like to Na-like ions. 26 2.5 Fitting strategy . 27 2.6 Results and discussion . 28 2.6.1 Total RR rates. 28 2.6.2 Level-resolved RR rate coefficients. 28 2.7 Summary . 30 References. 30 3 The electron energy loss rate due to radiative recombination 33 3.1 Introduction . 35 3.2 Methods . 37 3.2.1 Cross sections. 37 3.2.2 Rate coefficients . 38 3.3 Results . 39 3.3.1 Parameterization . 41 3.4 Discussions . 45 3.4.1 Comparison with previous results . 45 3.4.2 Scaling with 푧 . 51 3.4.3 Radiative recombination continua . 51 3.4.4 Total radiative recombination rate. 56 References. 57 vii viii Contents 4 Density diagnostics of ionized outflows in active galactic nu- clei: X-ray and UV absorption lines from metastable levels in Be-like to C-like ions 59 4.1 Introduction . 61 4.2 Methods . 63 4.3 Results . 63 4.3.1 Be-like . 63 4.3.2 B-like . 69 4.3.3 C-like . 69 4.3.4 Summary . 73 4.4 Discussion. 76 4.4.1 Ionization parameter dependence . 76 4.4.2 Domain of density and ionization parameter diagnostics 79 4.5 Density diagnostics for the ionized outflow in NGC 5548 . 80 4.A N-like Fe XX to F-like Fe XVIII . 84 4.B Comparison of the level population calculation with CHIANTI . 89 References. 91 5 Anatomy of the AGN in NGC 5548: IX. Photoionized emission features in the soft X-ray spectra 93 5.1 Introduction . 95 5.2 Observations and data reduction . 98 5.3 Spectral analysis and results. 98 5.3.1 Phenomenological local fit . 99 5.3.2 Physical global fit. 100 5.4 Discussion. 109 5.4.1 In relation to the optical NELR . 109 5.4.2 In relation to the X-ray warm absorber . 112 5.4.3 Unobscured SED for the X-ray emitter . 114 5.4.4 Charge exchange component? . 116 5.5 Summary . 116 References. 117 6 Photoionized emission and absorption features in the high- resolution X-ray spectra of NGC 3783 121 6.1 Introduction . 122 6.2 Observations and data reduction . 123 6.3 Spectral analysis . 124 6.3.1 Optical to X-ray spectra construction. 126 6.3.2 Description of model components . 127 6.4 Results and discussions. 129 6.4.1 Intrinsic broadband SED of the AGN . 129 6.4.2 Warm absorber . 132 6.4.3 X-ray photoionized emitter . 137 6.4.4 Variability of the X-ray emission features . 142 6.4.5 Summary . 146 Contents ix 6.5 Conclusions . 148 6.A Component relation in fitting the spectra using SPEX . 148 References. 149 7 Nitrogen abundance in the X-ray halos of clusters and groups of galaxies 153 7.1 Introduction . 154 7.2 Data reduction . 156 7.3 Spectral analysis . 156 7.4 Results and comparison with literature values . 158 7.5 Discussion. 162 7.5.1 ICM Chemical enrichment . 162 7.5.2 Origin of nitrogen enrichment . 166 7.5.3 Odd-푍 elements . 172 7.6 Conclusions . 175 7.A Global spectral fit. 180 7.B Systematic uncertainties in spectral analysis . 182 7.B.1 Differential emission measure distribution. 182 7.B.2 Spatial broadening model . 182 7.B.3 RGS background model . 186 7.C EPIC spectral analysis of NGC 5044 with SPEX v3.03 . 188 7.D IMF weighted SNcc yields and yields of SNIa. 189 References. 189 Summary 195 Samenvatting 199 Curriculum Vitæ 203 List of Publications 205 Acknowledgements 207 1 Introduction 1 2 1. Introduction 1 1.1. Hot astrophysical plasmas in X-rays Hot astrophysical plasmas pervade the Universe: about half of the baryonic content in the Universe is expected to have a temperature of 푇 > 10 K, which is largely un- detectable by observational facilities at wavelength longer than X-rays (0.1–100 Å). The X-ray band therefore provides unique opportunities to find clues to answer ma- jor astrophysical questions like “How does AGN feedback influence the host galaxies and beyond?” and “What is the chemical composition of the Universe and what are the origins of these elements?”. X-ray spectroscopy enables us to constrain physical properties (temperature, density, abundance, microscopic turbulence, line of sight velocity, etc.) of these hot plasmas. Thanks to the grating spectrometers aboard XMM-Newton (den Herder et al. 2001; Mason et al. 2001; Strüder et al. 2001) and Chandra (Brinkman et al. 2000; Canizares et al. 2005), our knowledge of the hot and energetic Universe has advanced in the past two decades. We are also looking forward to new missions like Arcus (Smith et al. 2016), Astro-H (also known as Hitomi, Takahashi et al. 2014), and Athena (Nandra et al. 2013), which are built on new technologies. Compared to the current generation of spectrometers, the next generation improves the spectral resolution by one or two orders of magnitude so that blended spectral features can be clearly resolved. High quality spectra from both current and future generations of X-ray spec- trometers challenge plasma models that are widely used in the community. More accurate and complete atomic data are required to build better plasma models. Otherwise, the interpretation of the physical properties of the plasmas might be incorrect. When I started my PhD project in 2014, the Hitomi satellite was scheduled to be launched in 2016. There was and still is an urgent need for improvements on the SPEX code. SPEX is a software package, including atomic data and various plasma models, designed for the analysis and interpretation of high-resolution cosmic X- ray spectra. My first project was to update the radiative recombination data in the SPEX code. Radiative recombination is a fundamental atomic process, therefore, almost all plasma models are affected by the accuracy and completeness of the ra- diative recombination data. We aimed to test the updated SPEX code by measuring the chemical abundances in the CHEERS sample (de Plaa et al. 2017) of clusters observed with XMM-Newton at that time and apply to Hitomi data when they are available. While I made progresses on updating the radiative recombination data in SPEX 1.2. Active Galactic Nuclei and circumnuclear media 3 and commenced on studying the nitrogen enrichment of the CHEERS sample in my second year as a PhD student, Hitomi spun out of control about forty days af- 1 ter its successful launch. Although I did not work directly on the Perseus spectra observed with the Soft X-ray Spectrometer aboard Hitomi, the updated collisional ionization plasma model in the SPEX code has been applied to the Perseus spec- tra which lead to several high profile publications (e.g., Hitomi Collaboration et al. 2017a,b). I decided to shift my focus to Active Galactic Nuclei (AGN) since there are still many interesting questions to be answered with photoionization modeling of high-resolution X-ray spectra of AGN obtained with the current generation of spectrometers aboard Chandra and XMM-Newton. For instance, it was recently dis- covered that some Seyfert 1 galaxies have a special type of photoionized outflow, which heavily obscures the soft X-ray continuum and causes simultaneous deep, broad UV absorption troughs (e.g., Kaastra et al. 2014; Mehdipour et al. 2017). As a result, X-ray narrow emission lines stand out above the diminished continuum. Such a special state of the AGN offers a unique opportunity to study relatively weak narrow emission lines in the soft X-ray band that are previously hidden by the un- obscured continuum. 1.2. Active Galactic Nuclei and circumnuclear me- dia The center of almost every galaxy, except for the smallest ones, contains a super- massive black hole (SMBH) with 푀 > 10 M⊙. The growth of the supermassive black hole is realized via accretion of matter. When the accretion rate is above a certain limit (≳ 10 Eddington ratio), the central region of this active galaxy is called an active galactic nucleus (AGN). The rich phenomenology of AGN, cover- ing the entire electromagnetic spectrum, is intriguing yet puzzling.