unless otherwise instructed Radiative Processes

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ASTR 6200 Astrophysical Radiative Processes Fall 2019 Time: Mondays 2:20 - 5:20 PM Venus: 501 Second General Building Webpage: http://orion.astr.nthu.edu.tw/arp/ 1 C ourse Plan Instructor & TA Vivien Chen Oce: 513 Second General Building Phone: (03) 574-2518 Email: [email protected] Oce hour: 10:30-11:30 Thursdays TA Oce: Second General Building Email: Oce hour: 2 C ourse Plan Class Policy Grading 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 3 C ourse Plan Textbook and References Textbook 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 & Sons Stellar Atmospheres by D. Mihalas 1978, Freeman (out of print) 4 C ourse Plan

Transcript of unless otherwise instructed Radiative Processes

Page 1: unless otherwise instructed Radiative Processes

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

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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

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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

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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

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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.