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Edwina Golden
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7 ACTIVE GALACTIC NUCLEI I. AN INTRODUCTION Sebastian F. Hoenig Lecturer & Marie Curie Fellow

8 Outline and learning goals I. Phenomenology What are AGN? How are they identified? II. Energy output Where is the energy coming from? In which wavebands does the energy get radiated out? III. The AGN zoo and unification How can we make sense of the different AGN types? IV. The dusty torus Why is it interesting? Where is the radiation coming from? What is its structure? V. AGN in the cosmological context Why should the universe (and funding agencies) care about black holes?

9 I. Phenomenology

10 I. Phenomenology HST/NASA/ESA Bill Keel

11 I. Phenomenology HST/NASA/ESA Bill Keel

12 II. Energy output

13 II. Energy output luminosities of erg/s (about Lsun) How much energy is this over a year? How does this compare to a SN?

14 II. Energy output luminosities of erg/s (about Lsun) How much energy is this over a year? How does this compare to a SN? Idea: convert mass into energy

15 II. Energy output luminosities of erg/s (about Lsun) How much energy is this over a year? How does this compare to a SN? Idea: convert mass into energy Efficiencies: Ṁ M /yr 6 L erg/s 0.1 nuclear fission nuclear fusion accretion accretion onto massive compact object

16 II. Energy output How massive? consider balance of radiation pressure and gravity on ionised gas

17 II. Energy output How massive? consider balance of radiation pressure and gravity on ionised gas What spectrum? M M L erg/s T 10 4 K optical + UV emission from accretion onto a supermassive black hole

18 II. Energy output

19 II. Energy output

20 II. Energy output???? disk corona

21 III. AGN zoo and unification

22 III. AGN zoo and unification HST/NASA/ESA

23 III. AGN zoo and unification HST/NASA/ESA Carilli & Barthel

24 III. AGN zoo and unification

25 III. AGN zoo and unification Bill Keel

26 III. AGN zoo and unification Bill Keel

27 III. AGN zoo and unification A Zoo of AGN classes Unification scheme putting everything in one picture

28 III. AGN zoo and unification A Zoo of AGN classes Unification scheme putting everything in one picture

29 IV. The dusty torus

30 IV. The dusty torus Let s simplify a bit accretion disk (optical and ultraviolet radiation) dusty torus (infrared radiation)

31 IV. The dusty torus How is the IR emission coming together? Dust absorbs in the optical/uv

32 IV. The dusty torus How is the IR emission coming together? Local thermal equilibrium = what goes in has to get out again

33 IV. The dusty torus How is the IR emission coming together? Local thermal equilibrium = what goes in has to get out again L 4 r 2 =4 Q abs;p(t ) SB T 4

34 IV. The dusty torus How is the IR emission coming together? Local thermal equilibrium = what goes in has to get out again L 4 r 2 =4 Q abs;p(t ) SB T 4 inner radius: take T = Tsub = 1500 K and (modified) Stefan-Boltzmann law (= rewrite the equation above)

35 IV. The dusty torus How is the IR emission coming together? Local thermal equilibrium = what goes in has to get out again L 4 r 2 =4 Q abs;p(t ) SB T 4 inner radius: take T = Tsub = 1500 K and (modified) Stefan-Boltzmann law (= rewrite the equation above) r sub 0.2pc L 1/ erg/s 2 Tsub 1500 K 1/2 s 1.0 the torus is parsec-scaled (=mas in nearby AGN)

36 IV. The dusty torus Where does it end? How much mass is in there? From X-rays and optical absorption: H column density ~10 24 particles/cm 2

37 IV. The dusty torus Where does it end? How much mass is in there? From X-rays and optical absorption: H column density ~10 24 particles/cm 2 2 M torus Rtorus N H M pc cm 2 M torus 10 5 M Rtorus 10 r sub 2 L erg/s N H cm 2 mass supply to AGN:

38 Where does it end? How much mass is in there? From X-rays and optical absorption: H column density ~10 24 particles/cm 2 2 M torus Rtorus N H M pc cm 2 mass supply to AGN: IV. The dusty torus M torus 10 5 M Rtorus 10 r sub t supply years 2 L erg/s Rtorus 10 r sub 2 N H cm 2 N H cm 2

39 Where does it end? How much mass is in there? From X-rays and optical absorption: H column density ~10 24 particles/cm 2 2 M torus Rtorus N H M pc cm 2 mass supply to AGN: IV. The dusty torus M torus 10 5 M AGN phase ~ years Rtorus 10 r sub t supply years 2 L erg/s Rtorus 10 r sub 2 N H cm 2 N H cm 2 torus must be constantly refilled

40 V. AGN in the cosmological context

41 V. AGN in the cosmological context supermassive black hole < 1% of mass of galactic bulges black hole mass black hole mass Häring & Rix turbulent motion of stars in galaxy centre stellar mass in central galaxy AGN and galaxies coevolve

42 V. AGN in the cosmological context supply and suppression via star formation very luminous AGN are in starburst galaxies

43 V. AGN in the cosmological context luminosities evolve over time Hasinger highest masses first??

44 V. AGN in the cosmological context

Astr 2320 Thurs. April 27, 2017 Today s Topics. Chapter 21: Active Galaxies and Quasars

Astr 2320 Thurs. April 27, 2017 Today s Topics Chapter 21: Active Galaxies and Quasars Emission Mechanisms Synchrotron Radiation Starburst Galaxies Active Galactic Nuclei Seyfert Galaxies BL Lac Galaxies