Hard-core atomic physics: highly charged ions José R R. C Crespo L po López-Urr pez-Urrutia tia Max-Planck-Inst x-Planck-Instit itut fü für Ke r Kernph rnphysik ysik Heid Heidelberg rg
• Gamma-ray bubbles extend 50,000 light-years. • Hints first observed in X-rays (blue) by ROSAT • Gamma rays mapped by Fermi (magenta) You are here
1869: Harkness & Young collect spectra of the solar corona
Which element is so light that it overcomes the Sun‘s gravity? Coronium was postulated for the green coronal line at 530.3 nm which was found Edlén and Grotrian explained it in the 1940‘s B. Edlén, Z. Astrophys. 22 22, 30 (1942)
What are highly charged ions? • Atoms loose many electrons at high temperatures < 100000 K due to collisions • The incomplete electronic shell does not compensate the positive nuclear charge • The electronic structure of such positive ions with few electrons behaves like that of an atom Example: Fe XXV = Fe 24+ ion From 26 electrons to only two electrons: Helium-like 1s 2
Highly charged ions (HCI) HCI: • size: few pm, • positive charge • few strongly bound electrons Atom: (keV) • size: 100 pm, • strong electron- • outer electrons weakly bound (10 eV) nucleus overlap
Need for experimental data • Relevant and precise experimental data needed for theory tests • Fundamental phenomena become accessible to observation: • simpler electronic structure • scaling with high powers of Z
The classic ideal: H-like ions blem analytical solutio Two-b Two-body dy-Coulomb-Pr -Coulomb-Problem analytical solution Scaling factors Scaling factors from H from H to to U 91+ 91+ : ´ 8 10 •Level energy Level energy E n ~ Z ~ Z 2 2 ´ 8 10 3 Transiti Transition on probabi probabilit ity A ik ik : ´ 7 10 • E1 E1 ~ ~ Z 4 a factor a factor of of 10 7 ´ 6 10 2E1 ~ Z 6 10 11 11 • 2E1 ~ ´ 6 ´ 4 10 • M1 M1 ~ ~ Z Z 10 10 ´ 4 10 19 19 ´ 5 10 • M2 M2 ~ ~ Z Z 8 8 ´ 5 10 15 15 ~ Z 3 • hyperfin hyperfine splittin e splitting g ~ • nuclear size nuclear size effects effects ~ ~ Z 6 • QED contrib QED contribution tions s ~ ~ Z 4 • PNC contrib PNC contribution tions s ~ ~ Z 5 „forbidden“ lines „forbidden“ lines (Sun) (Sun)/ (H atom) (H atom)
Why highly charged ions? Schrödi Sch ödinger nger Dirac Dirac QED ED . Z 2 /n + r relati tivi vity ty +radi +radiation fiel field E n = R = R y /n 2 n=3 n=3 n=2 n=2 p 3/2 p 3/2 3/2 3/2 s 1/2 1/2 s 1/2 1/2 , p , p 1/2 p 1/2 1/2 1/2 Lamb shift Lamb shift 115 115 keV keV n=1 n=1 131.8 131 .8 keV keV 132 132.3 .3 keV keV s 1/2 1s Lamb shift 1s Lamb shift 1/2 92+ 468 eV for U for U 92+ 468 eV
Lamb shift in hydrogen- and lithium-like ions H-like Li-like Lamb shift QED » QED Lamb shift Li: 0.002% of 1.85 eV QED contributions: Fe 23+ : 1% of 48.6 eV U 89+ : 15% of 280 eV
Scaling laws: Effects grow as powers of atomic number Z Z 2 10 eV 140 keV • binding energy • correlation nearly Z independent • relativistic fine structure Z 4 eV keV Z 4 eV 300 eV • QED Z 3 eV 5 eV • hyperfine structure Z 5 eV 200 eV • nuclear size effects • Forbidden transition probabilites Z 10 up to a factor 10 18 1 2 H He 3 4 5 6 7 8 9 10 The relative weight of these Li Be B C N O F Ne effects can be tuned 11 12 13 14 15 16 17 18 Na Mg Al Si P S Cl Ar 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe 55 56 * 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 Cs Ba Lu Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn 87 88 * 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 Fr Ra * Lr Rf Db Sg Bh Hs Mt Ds Rg Cn Uut Uuq Uup Uuh Uus Uuo
Why photon spectroscopy beyond hydrogen? - Non-perturbative Q -perturbative QED: D: co coupling co ling constant tant Z α ≈ 1 1 Bound e und electr ectron on expanded: panded: sum o of free e ee electron p ectron propagators agators Many ny virtual p rtual photons, e otons, each i ch interaction teraction Z t Z times st stronger t ronger than an in H H •Few-particle QED unexplored •Theory of (non-perturbative) QED in high fields still under construction; general scaling law ~ Z 4 •Large nuclear size effects
In the Universe, elements are mostly highly ionized: Highly charged ions (HCI) • Interior of the Sun (15 MK) • Solar corona (2 MK) • Solar wind (MK) • Supernova remnants • Active galactic nuclei (100 MK) • Warm-hot intergalactic medium (0.1-1 MK) In the laboratory: • Fusion machines (50 MK) • Accelerators, laser produced plasmas (1 MK) • Electron beam ion traps (e. g. in Heidelberg)
Baryonic matter (“atoms” ) is mostly highly ionized in the intergalactic medium, galaxy clusters and galaxies Warm-hot intergalactic medium at 10 5 to 10 8 K Galaxies consist of: 90% ionized hydrogen 10% stars 0.01% planets Compilation of current observational measurements of the low redshift baryon census (Shull, Smith, & Danforth, ApJ 2012)
Hitomi SXS spectra of the Perseus cluster of galaxies X-ray lines from H-like, He-like and Li-like ions kT e = 3.97 ± 0.02 keV Fe/H= 0.63 ± 0.01 (relative to solar abundance) Solar abundance ratios of the iron-peak elements in the Perseus cluster Hitomi Collaboration, Nature (2017)
Supernova explosions disperse the elements 3 light years Nordic Optical Telescope and Romano Corradi Cat‘s Eye Nebula (Isaac Newton Group of Telescopes, Spain) NASA Image, Hubble ST, Cat's Eye Nebula
Supernova remnants, hot shocks X rays Cassiopeia nebula: X ray telescope XMM Remnant of the1680 AD supernova orbiting Earth X-RAY: NASA/CXC/SAO; visible: NASA/STScI; infrared: NASA/JPL-Caltech/Steward/O.Krause et al.
Supernova remnants (Tycho)
Warm-hot intergalactic medium
Photoabsorption lines due to warm-hot intergallactic medium are due to highly charged ions hot, photoionized intergallactic medium Observer Blazar H2356-309: Line-of-sight crosses the Sculptor Wall, a large-scale superstructure of galaxies at z ~ 0.03 AAMOP 2011 ‐ 2012 2011 ‐ 11 ‐ 02 24 Date: 11 May 2010, Satellite: XMM-Newton; artist's impression of WHIM in the Sculptor Wall Spectrum: NASA/CXC/Univ. of California Irvine/T. Fang. Illustration: CXC/M. Weiss
How to detect WHIM For very tenuous media, measurements in absorption are far more sensitive than those in emission X-ray observatory Backlighting quasar absorbing 3.7 4.5 medium Spectrum shows absorption lines Total absorption yields column density information
HST + Chandra Deep Field South: X-ray View There are X-ray sources (shown in blue) outshining whole galaxies
A primer on black holes • Black hole: Million times the solar mass • Event horizon 100 times solar radius • Accretion disk size: light days • Jets: 10 5 light years • 100 light days away: Broad line region • 100 light years: Molecular torus • Narrow line region • Event horizon of central black hole in NGC 3783 has a diameter 100 times that of the Sun • It produces more radiation than 10 9 suns
Size matters The first black hole, Cygnus X-1, was observed more than 40 years ago with Aerobee rockets (Bowyer et al., 1965)
Radiotelescopes can interferometrically resolve the near structure
Magnetic spinning in BH jets
UFOs exist! Ultra-fast outflows (UFOs) (ESA image) Supermassive black holes produce narrow particle jets (orange) and wider streams of gas (blue-gray) which can regulate both gallactic star formation and the growth of the black hole F . Tombesi et al., ApJ, MNRAS 2010,2011,2012
Size matters
Relativistic Doppler shifts The broad line region (BLR) shows very large Doppler shifts due to high velocity fields
Averaged spectral profile of Lockman hole AGN
Fe XXVI ions moving at 0.66 c in an AGN • Ratio of data to model results for two XMM-Newton observations. Dotted lines: rest energy of the transitions of Fe XXVI (6.97 keV) and Ni XXVII (7.74 keV). • Flux ratio between blue- and redshifted components of Fe XXVI is consistent with predicted Doppler boost in a jet. MD Trigo et al. Nature 504 504, 260 (2013)
Line profiles Relativistically broadened emission lines near BHs • Dominant feature: Fe K α at 6.4 keV • Observed in active galactic nuclei, and galactic BHs with ASCA, RXTE, XMM, Chandra, Suzaku
Line profiles show accretion disk dynamics •Gravitational red shift •Radiation from the backside bent towards observer •Rotation causes red and blue wings •Intensity depends on distance from center
Black hole rotation leaves spectral imprint •Black hole spin lets accretion disk approach more the event horizon •Line profile is modified by space-time frame rotation around BH
Full general relativistic models can explain the lines shapes and the morphology of AGN observer From: Thomas Dauser, PhD thesis, Bamberg, Erlangen
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