ASTR 6200 Astrophysical Radiative ProcessesFall 2019
Time: Mondays 2:20 - 5:20 PM Venus: 501 Second General Building Webpage: http://orion.astr.nthu.edu.tw/arp/
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Course Plan
Instructor & TAVivien Chen ���
Office: 513 Second General Building Phone: (03) 574-2518 Email: [email protected] Office hour: 10:30-11:30 Thursdays
TA�Office: Second General Building Email: Office hour:
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Course Plan
Class PolicyGrading policy
Problem sets: 70% Final examination: 30%
Problem sets are due 5PM Wednesday of the following week unless otherwise instructed
Late problems will not be accepted unless there is a valid excuse approved by the instructor prior to the deadline
15 lectures in total Class cancelled on September 23 and November 25 Holidays on April 8 and April 29
Final examination on June 10
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Course Plan
Textbook and ReferencesTextbook
Radiative Processes in Astrophysics by G. B. Rybicki & A. P. Lightman 1979, John Wiley (electronic version available on campus)
References An Introduction to Modern Astrophysics (2ed) by Carroll & Ostlie 2007, Pearson Classical Electrodynamics (2ed) by J. D. Jackson 1975, John Wiley & SonsStellar Atmospheres by D. Mihalas 1978, Freeman (out of print)
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Course Plan
Course OutlineFundamentals of radiative transfer Basic theory of radiation fields Radiation from moving charges Bremsstrahlung Synchrotron radiation Compton scattering Plasma transfer effects Radiative transitions Advanced topics on radiative transfer and line formation
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Course PlanAstrophysical Systems
Astronomical phenomena Emission mechanisms
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Chapter 0 Astrophysical Phenomena
The Sun
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Astrophysical Phenomena
The Sun as a Reference�8
Property Value
Mass M� = 1.99 × 1033 gRadius R� = 6.96 × 1010 cmLuminosity L� = 3.90 × 1033 erg s-1 Effective temperature Teff = 5780 KAge t� = 4.55 × 109 yrCentral density ρc = 1.48 × 102 g cm-3 Central temperature Tc = 15.6 × 106 KCentral pressure Pc = 2.29 × 1017 dyn cm-2
Astrophysical Phenomena
Stellar Spectral Types�9
(early) O B A F G K M L T Y (late) Stars (a.k.a. dwarfs): OBAFGKMBrown dwarfs: LTYFollowed by subclass 0, 1, ..., 9
Credit: KPNO 0.9-m Telescope, AURA, NOAO, NSF
Astrophysical Phenomena
Thermal Emissions�10
High Energy Astrophysics 2ed, Longair 1992, Cambridge
Astrophysical Phenomena
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R&L Fig. 1.1
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Hertzsprung-Russell Diagram Astrophysical Phenomena
Stellar Evolution�12
http://chandra.harvard.edu/photo/2007/sn2006gy/more.htmlAstrophysical Phenom
ena
Generations of Stars�13
Important role of stars: enrich the interstellar medium (ISM) with heavy elements (metals)
Credit: Wolfgang Brandner (JPL/IPAC), Eva K. Grebel (U of Washington), You-
Hua Chu (UIUC), ѿ NASA
Astrophysical Phenomena
Interstellar Medium
Display of ISM Absorption: dark clouds Scattering: reflection nebulae Emission: emission nebulae
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Credit: Daniel Verschatse (Antilhue Observatory)
Astrophysical Phenomena
Crab Nebula (SN 1054)Expansion velocity ~ 1450 km s-1 Luminosity ~ 8×104 L⊙, mostly highly polarized synchrotron radiation
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Credit: NASA - X-ray: CXC, J.Hester (ASU) et al.; Optical: ESA, J.Hester and A.Loll (ASU); Infrared: JPL-Caltech, R.Gehrz (U. Minn)
http://antwrp.gsfc.nasa.gov/apod/ap061026.html
Astrophysical Phenomena
Electron Energy SpectrumRelativistic electrons produced in high energy processes and modulated by ISM
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Astrophysical Phenomena
Active Galactic Nuclei�17
Centaurus A
Credit: X-ray - NASA, CXC, R.Kraft (CfA), et al.; Radio - NSF, VLA, M.Hardcastle (U Hertfordshire) et al.; Optical - ESO, M.Rejkuba (ESO-Garching) et al.
Astrophysical Phenomena
Cosmic Microwave Background�18
Astrophysical Phenomena
1991ApJ...371L...1S
Smoot et al. 1991, ApJ, 371, L1
2006 Nobel Prize
Laureates
George F. Smoot
CMB Map from COBE�19
1990ApJ...354L..37M
Mather et al. 1990, ApJ, 354, L37
2006 Nobel Prize
Laureates
Astrophysical Phenomena
"for their discovery of the blackbody form and anisotropy of the cosmic microwave background radiation"
John C. Mather
Sunyaev-Zel’dovich Effect�20
Carlstrom, Holder, & Reese 2002, ARA&A, 40, 643
Astrophysical Phenomena
Distortion in the Cosmic Microwave Background due to photons being inversely Compton-scattered by electrons in the hot gas that pervades the rich clusters.