Quaar and Active Galactic Nuclei Seyfert Galaxie Carl Seyfert, 1940 Spiral Very bright unreolved nucleu Strong emiion line High ionization tate Broad line = large internal velocity diperion 10,000 km/ O + Type Jut narrow emiion line O ++ N + Type 1 Broad + narrow emiion line Fe +6 Ne +4 3 NGC 1097 Gemini J-band image + diffraction ring?? H energy level 1 Quaar Luminoity = (apparent brightne) x ditance Apparent brightne: Dicovered quaar from their radio emiion. Radio poition Orion nebula redhift = 0 3C 73 But which object??? Quaar Lunar occultation 3C 73 Redhift = 0.158 Parke, Autralia 10 radio telecope. Wavelength Ditance: Now meaure optical pectrum Doppler hift of wavelength of light velocity of receion (redhift) due to expanion of Univere. huge ditance huge luminoity! Apparent brightne 1
Quaar and Active Galactic Nuclei Seyfert Galaxie Carl Seyfert, 1940 Spiral Very bright unreolved nucleu Strong emiion line High ionization tate Broad line = large internal velocity diperion 10,000 km/ O + - Homework 7 due Tueday. - Study guide now on web. - Evaluation: http://ironline.mu.edu Type Jut narrow emiion line O ++ N + Quaar 1960 example: 3C 73 Bright (m ~ 13 mag) Stellar appearance on image Seyfert-like pectrum Redhift HUGE luminoity 1000x Milky Way luminoity. Type 1 Broad + narrow emiion line Ne +4 Fe +6 Active Galactic Nuclei (AGN) Claification Quaar = Quai Stellar Radio Source QSO = Quai Stellar Object radio-quiet 1000 of time more numerou than Quaar Blazar (or BL Lac object) bright continuum ource, but no emiion line Seyfert Galaxie Type 1 and Radio galaxie Viible X-ray etc Radio Blackbody Defining feature = non-thermal continuum Strong in Quaar, QSO Weaker in Seyfert, radio galaxie Cygnu A
Meaured Propertie Rapid brightne change (week, day. hour). QSO are mot luminou object in univere on 10 7 yr timecale. [CO Fig. 8.16] Not detectable [CO Fig. 8.19] Milky Way 3C 73 Time Size = light-week, light-day, light-hour. In center of galaxie HST image What are they? Ga, tar fall into 10 6-10 8 M un black hole. Grav. energy i releaed [Fig 8.3] [Fig 8.4] [Fig 8.5] Black hole Accretion dik Broad emiion-line region Obcuring toru Narrow emiion-line region 3
Black Hole [CO 17.3] Exploring Black Hole An Introduction to General Relativity by Taylor & Wheeler (TW) Excellent treatment uing imple calculu. AST 860 Gravitational Atrophyic Prof. Loh TuTh :40-4:00 Textbook i Hartle Gravity, An Introduction to Eintein General Relativity What happened to Saturn? Black Hole & the Schwarzchild Metric Simplified metric, from Taylor & Wheeler (no c, no G, no ): Schwarzchild radiu: R S = M Schwarzchild coordinate recontructed a if een from a point where pace i flat. imagine concentric hell of radiu r 1, r, r 3 hell radiu defined to give correct urface area 4r r 4 r 3 r r 1 r 5 But for an oberver in free-fall: Metric = flat pace-time in local region (i.e. pecial relativity). d = dt dr r d In oberver free-falling frame, dr = d = 0. So time on oberver writwatch = =. d 4
Energy a a Contant of Motion ( leaving out contant c, G, and dimenion ) Newtonian: Total energy per unit ma = = contant Example: Special Relativity d = dt dr r d + object follow geodeic: = extremum E dt m d Schwarzchild Geometry + object follow geodeic: = extremum E m M 1 r dt d Atronaut Falling into a Black Hole Schw. conervation of energy: Schw. metric Eq. of motion for freefall in Schw. Coord: Homework Q. 1: Show thi Homework Q. : Show thi [CO 17.0] For free-falling atronaut, time tep on writwatch = d, o velocity i: r A een by atronaut Time (m) A een from afar 5
Schw. metric Schw. conervation of energy: Orbit around black hole (from TW) Schw. conervation of angular mom: Effective potential Newtonian V/m or E/m 0.08 0.04 0 -(L/m) /(r ) Total Eff. Potential V/m 0 40 r/m [TW, Fig 4-5] Remember [CO 5.3] dicuion of epicycle. -0.04 Homework Q. 3: Show thi Schwarzchild -0.08 1.04 -M/r [TW, Fig 4-1] Newtonian V/m + 1 1.04 [TW, Fig 4-13] L/m = 4.33M Preceion of perihelion Innermot table orbit V/m or E/m 0.94 E/m of pacehip Schw, V/m for L/m = 4.0M 0 10 0 r/m 4.0M 0.94 3.464M 0 5 10 r/m Notation: No G, no c Kerr metric (1963) Spinning Black Hole dd cro term frame dragging A fond memory: where J = Angular Momentum Maximal pin: J max = M (or = GM /c in CO unit) Uually ~ the cae. Then Event Horizon in equatorial plane i at r=m Infalling particle with no angular momentum: [CO 17.] Static limit Frame-dragging c Ergophere E/m Remaining energy (ret radiated away) [TW, pg. F-14] r = M r = M+(M -a ) 1/ (unrealitic cae with untable orbit, but give an etimate of available energy) r/m Both plot for equatorial plane only 6
E/mc Remaining energy (ret radiated away) Innermot table orbit Schw Kerr Kerr black hole particle horizon rc /GM The Accretion Dik Convert gravitational energy into light. [Fig 6.17] Black Hole Accretion dik + Black Hole + Jet Accretion dik Accretion Dik Dik material loe energy by black body radiation L( r) T ( r) 4 r dr Well-tudied phenomena in local binary tar ytem cataclymic variable Angular momentum material cannot fall directly onto central ma. Binary tar thin accretion dik Material work it way in toward center due to vicoity. For QSO: Material eventually fall into Black Hole From innermot table orbit log T (K) 5 4 T ( r) r 3/ 4 total radiation = um of black bodie. r hotter cooler [Fig. 18.13] Luminoity [CO pg. 661-665] [Fig. 18.14] log r log (nm) Binary tar reult, but QSO are imilar. 7
Continuum Source Cloud of relativitic electron Thermal radiation from dut X-ray from invere Compton cattering [Fig. 8.3] Log F Synchrotron radiation from jet Thermal radiation from dik X-ray from invere Compton cattering [Fig. 8.4] Log frequency Energetic Accretion rate & luminoity. ma fall into black hole: dm dt L dik c. Mc. 0.1 M 110 M yr -1 Eddington limit. Radiation preure = gravity: L GmM m Edd BH 4 r 4r aborption cro-ection Luminou QSO: L ~ L Edd Seyfert, Radio Galaxie: L << L Edd 8