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Published on November 14, 2007

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Solving Quasars part I:  Solving Quasars part I Martin Elvis Harvard-Smithsonian Center for Astrophysics in particular… Understanding Quasar Atmospheres Elvis M., 2000, Astrophysical Journal 545, 63 Fermilab Colloqium 29 October 2003 Quasars* unsolved after 40 years:  Quasars* unsolved after 40 years Once were a `hot topic’ Were the first to start the downfall of Steady State Cosmology - via ‘evolution’: change in density with cosmic time Now astronomers have moved on to easier problems – Large scale structure, Dark Energy and Gamma-ray bursts Quasar studies continue to generate many papers …but little understanding? Discovered in 1963 Quasars are the most powerful continuous radiation sources in the Universe * Note for the pedantic: By ‘quasars’ I mean all types of ‘activity’ in galaxies Fermilab Colloqium 29 October 2003 What’s the problem?:  What’s the problem? Enormous array of detail We have no images of a quasar atmosphere Would need 1000 times sharper pictures than Hubble or Chandra <100mas Must rely on spectra: span all wavelengths: X-ray - optical - radio Superficial understanding Fermilab Colloqium 29 October 2003 Why Study Quasars?:  Why Study Quasars? We live on a planet A star gives us life Galaxies dominate the Universe … but why do quasars matter? Here are 4 answers: Fermilab Colloqium 29 October 2003 Slide5:  Outside the wavelength range that our eyes are sensitive to 1. An Astronomer’s Answer Quasars dominate the night sky Fermilab Colloqium 29 October 2003 2. An Astrophysicist’s Answer:  2. An Astrophysicist’s Answer Gravity powered, not fusion. via Black Holes 106 - 109 as massive as the Sun. Gas heats up falling toward it, like a spacecraft on re-entry. Fermilab Colloqium 29 October 2003 The power available from gravity for heating is all too obvious following the Columbia tragedy 3. A Cosmologist’s Answer:  3. A Cosmologist’s Answer 4. A Physicist’s Answer:  4. A Physicist’s Answer Fermilab Colloqium 29 October 2003 Slide9:  What do we know? High level theory rapidly gave a clear picture massive black hole Lynden-Bell 1969 accretion disk Lynden-Bell 1969, Pringle & Rees 1972,Shakura & Sunyaev 1972 relativistic jet Rees 1967 [PhD], Blandford & Rees 1974 All established just 10 years after discovery Fermilab Colloqium 29 October 2003 Slide10:  does not connect to the atomic physics features observed in quasars This theory describes a naked quasar Leaves us with no way to order observations, nothing to test Fermilab Colloqium 29 October 2003 Atomic features in Quasar Atmospheres:  Atomic features in Quasar Atmospheres High ionization: e.g. CIV, OVI Low ionization: e.g. MgII, Hb. Fermilab Colloqium 29 October 2003 All studied separately with separate telescopes Quasars have no temperature:  Compton gamma-ray Observatory Chandra Hubble MMT Sub-millimeter array VLA Quasars have no temperature Whipple 10 meter Slide13:  Blind men and the elephant. Manga VIII Hokusai, Katsushika (1760-1849) Wall, Tree, Rope, Spear, Snake, Fan Not having the complete picture can be misleading Fermilab Colloqium 29 October 2003 we need a ‘low theory’ that deals with the multitude of quasar details:  we need a ‘low theory’ that deals with the multitude of quasar details Just as there are textbooks on ‘Stellar Atmospheres’ we need the subject of ‘Quasar Atmospheres’ Takes more than 1 step. First build an observational paradigm i.e. what do the observations drive require of any theory? These optically thin features are all interconnected S = `quasar atmosphere’ Fermilab Colloqium 29 October 2003 A Paradigm for Quasar Atmospheres:  A Paradigm for Quasar Atmospheres Accretion disk Broad Absorption Lines Reflection features Narrow absorption lines X-ray `warm’ absorbers Broad Emission Lines hollow cone Elvis M., 2000, Astrophysical Journal 545, 63 X-ray/UV ionizing continuum NB: Independent of Unification Jets are not included no absorption lines A Geometric & Kinematic solution c.f. Rees relativistic jets for blazars/radio sources Can now re-construct this model using data not in Elvis 2000 Quasar Atmosphere Fermilab Colloqium 29 October 2003 Take a lesson from lab plasmas: use all the data:  Take a lesson from lab plasmas: use all the data  NSTX diagnostic instruments cover everything 2mm interferometer X-ray PHA X-ray crystal spectrometer Radiometer Thomson scattering Far infrared tangential Interferometer/polarimeter Visible spectrometer Vacuum UV survey spectrometer Grazing incidence spectrometer Tangential bolometer array Single channel visible Bremsstrahlung detector Polarimeter X-ray pinhole camera Soft X-ray arrays Fast tangential X-ray camera Reflectometer array Infrared cameras Princeton AGN Physics with the SDSS, 29 July 2003 12,277 Papers on Quasars since 1963* *ADS to 4/18/03, refereed only , search on abstract containing ‘quasar’ | ‘AGN’ :  12,277 Papers on Quasars since 1963* *ADS to 4/18/03, refereed only , search on abstract containing ‘quasar’ | ‘AGN’ 1/day. Now 2 per day = 5% of all astronomy papers Spam! Need filters--- Physical measurements Mass, length, density. Not ratios, column densities Favor absorption: advice from Steve Kahn c.1985 1-D spatial integral, not 3-D; blueshift = outflow Use Polarization Non-spherical geometry With these filters just a dozen papers define the structure of quasar atmospheres. Fermilab Colloqium 29 October 2003 1.Physical Measurements: BEL Velocity-radius relation:  1.Physical Measurements: BEL Velocity-radius relation Reverberation mapping shows Keplerian velocity relation in BELs Pole-on Broad Emission Lines close to Keplerian velocities ~1000 rs, Schwartzchild radii Fermilab Colloqium 29 October 2003 1.Physical Measurements: Angle:  1.Physical Measurements: Angle Pole-on Use VLBI + X-ray to get angle of jet to line of sight Rokaki et al. 2003 astroph/0301405 (2) Continuum drops as cos q EW=EW0[1/3 cosq(1+2cosq)]-1 limb darkened disk Ha does not  Ha scale height larger than disklike optical continuum But BLR is rotating  rotating cylinder? A highly non-equilibrium shape Simplest solution: BLR is in a rotating wind Rotation about jet axis c.f. Wills & Browne 1986, Brotherton 1996, McLure & Jarvis 2003 Ha polarization rotation also implies orbiting gas Smith et al 2002 Fermilab Colloqium 29 October 2003 2. Absorption Features:  2. Absorption Features Narrow UV lines High ionization CIV, OVI High ionization OVII,OVIII Outflow ~1000 km s-1 Seen in 50% of quasars Seen in same 50% of quasars Simplest solution: Same gas, 2 phases Princeton AGN Physics with the SDSS, 29 July 2003 Winds are common in quasars Chandra HETGS 850ksec spectrum of NGC 3783:  Chandra HETGS 850ksec spectrum of NGC 3783 Over 100 absorption features fitted by a 6 parameter model  One T~106 K and one T~104 K, in pressure balance to 5% Krongold, Nicastro, Brickhouse, Elvis, Liedahl & Mathur, 2003 ApJ, in press. astro-ph/0306460 2-phase gas in pressure equilibrium 2. Absorption: More Physics from X-rays Fermilab Colloqium 29 October 2003 Slide22:  Krongold, Nicastro, Brickhouse, Elvis, Liedahl & Mathur, 2003 ApJ, in press. astro-ph/0306460 2-phase gas in pressure equilibrium 2. Absorption: Pressure Balance Free parameters in blue If at same distance NGC 3783 Chandra HETG(MEG) spectrum solution Fermilab Colloqium 29 October 2003 2. Absorption: where is the wind?:  2. Absorption: where is the wind? Velocity dependent covering factors  Absorber is close to continuum source  absorber is moving transverse Wind is close to continuum, crosses line of sight Arav, Korista & de Kool 2002, ApJ 566, 699 Arav, Korista, de Kool, Junkkarinen & Begelman 1999 ApJ 516, 27 Fermilab Colloqium 29 October 2003 A quasar wind is like a flame:  A quasar wind is like a flame We are looking through a flow Apparent lack of change is a common handicap for astronomers the ‘Static Illusion’ e.g. expansion of the Universe, cluster cooling flows, quasar disks Fermilab Colloqium 29 October 2003 Emission lines: a thin wind?:  Emission lines: a thin wind? Narrow Line Seyfert 1 galaxies (NLSy1s) show broad, strongly blueshifted high ionization (CIV) lines Understandable as disk wind redshifted lines hidden by disk Low ionization lines from outer disk c.f. Collin-Souffrin, Hameury & Joly,1988 A&A 205, 19 Leighly & Moore 2003, ApJ submitted See: Gaskell 1982 Wilkes 1984 Low ionization MgII BELs are rotating, transverse, thin winds Fermilab Colloqium 29 October 2003 2. Absorption / 1. Physical Measurements: Wind Density,thickness:  2. Absorption / 1. Physical Measurements: Wind Density,thickness UV/X-ray absorption responds to continuum changes: photoionized Nicastro et al. 1999 ApJ, 512, 184 Absorbing wind is dense But responds with a delay = recombination/ionization time  density  ne~108 cm- 3 for OVIII ne~3x107 cm-3 for FeXVII X-ray continuum “OVII edge” “OVIII edge” time density + column density (~3x1022 cm-2)  thickness (~1015 cm) < distance to continuum Absorbing wind is narrow Fermilab Colloqium 29 October 2003 3. Polarization: X-ray absorbers:  3. Polarization: X-ray absorbers Absorption line quasars are highly polarized in optical: 1. Scattering off non-spherical distribution Edge-on structure 2. Pole-on objects must be unobscured  scatterer & obscurer: flattened & co-axial Leighly et al. 1997 ApJ 489, L137 Absorbers are seen edge-on Fermilab Colloqium 29 October 2003 Flattened, Transverse Wind  axisymmetry:  Flattened, Transverse Wind  axisymmetry A transverse wind suggests an axisymetric geometry: bi-cones looking edge-on see absorbers Wind does not hug disk pole-on: no absorbers  absorbers in all quasars Mathur, Elvis & Wilkes 1995 ApJ, 452, 230 Princeton AGN Physics with the SDSS, 29 July 2003 Absorbing wind is a bi-cone to 1st order Putting X-ray/UV absorber and BEL together:  Putting X-ray/UV absorber and BEL together Both are disk winds rising well above the disk plane Elvis 2000 ApJ 545, 63; Krongold et al. 2003 Similar Pressure: P( abs ) ~1015 = 104 K x 1011 cm-3 P(BELR)~1015 = 106 K x 109 cm-3 Matching Ionization Parameter, U: T/U( abs ) = 106 = T( abs ) ~106 K/ U( abs ) ~1 T/U(BELR)= 106 = T( abs ) ~104 K/ U(BELR) 0.04 Similar Radius: for NGC 5548 r( abs ) ~1015 - 1018cm recomb. time + NHX r(BELR)~1016cm CIV reverberation mapping Keep it simple: Emission and Absorption are 2 phases of the same quasar wind They share physical properties: Fermilab Colloqium 29 October 2003 Components of Quasar Atmospheres:  Components of Quasar Atmospheres High ionization: e.g. CIV, OVI Low ionization: e.g. MgII, Hb. In a 2-phase transverse wind in pressure balance United Fermilab Colloqium 29 October 2003 The Final Element: Broad Absorption Lines (BALs):  The Final Element: Broad Absorption Lines (BALs) Old question: Special objects? or Special angle? Ferland & Hamann 1999 Annual Reviews of Astronomy & Astrophysics , 37, 487 10% of quasars show BALs with doppler widths ~2%c - 10%c ~10x NALs. Clear acceleration (or deceleration) Fermilab Colloqium 29 October 2003 Broad Absorption Lines (BALs):  Broad Absorption Lines (BALs) BEL FWHM correlates with BAL velocity (at minimum flux) V(BAL) ~ 2 FWHM(BEL) Lee & Turnshek 1995 ApJ 453 L61 Princeton AGN Physics with the SDSS, 29 July 2003 BAL gas knows about BEL gas More BEL-BAL correlations: Reichard et al. 2003 BEL width BAL width 2:1 BALs from a rotating wind:  BALs from a rotating wind Redshifted BAL onset Possible occasionally in a rotation dominated wind Hall et al. 2002 ApJS, 141, 267 BALs need a rotating wind … like the BELs blue red Fermilab Colloqium 29 October 2003 3. Polarization: BAL troughs:  3. Polarization: BAL troughs Ogle et al. 1999 ApJS, 125, 1; Ogle 1998 PhD thesis, CalTech BAL troughs are highly polarized – scattered light off flattened structure => BALs are common. Universal? Scattering solves other BAL problems: ionization, abundances, NH Thomson thick: X-ray Fe-K, Compton hump Conical wind fits BALs well Hamann 1998 ApJ 500, 798; Telfer et al. 1998 ApJ 509, 132 Is the BAL wind itself the scatterer? Bi-cone model Predicts distribution of non-BAL quasar polarization Fermilab Colloqium 29 October 2003 3. Polarization: VBELR:  3. Polarization: VBELR Supported by observations: Emission lines twice as broad in polarized, non-variable light.  non-BAL quasars have Thomson thick gas at large, BAL, velocities Don’t see in absorption because out of our line of sight Large scattering region (but not too large, Smith et al. 2003 MNRAS) with BAL velocities Young et al. 1999 MNRAS 303, 227 BAL velocity gas exists in non-BAL quasars If BALs are cones, all quasars should have BAL gas Fermilab Colloqium 29 October 2003 One last, crucial, complication:  One last, crucial, complication Angles are wrong: BAL velocities too high: ~10,000 km s-1 10 times narrow absorption lines Requires extreme cone opening angle. Simple solution: bend wind Predicts: 1. ‘detached BALs’* = Lowest velocity where wind bends into our line of sight = vertical velocity from disk 2. ~10% covering factor dr at r gives 6o divergence angle radiation forces gas to diverge Both previously unexplained *Could this be an ionization effect? Dv a IP? Fermilab Colloqium 29 October 2003 Quasar Atmospheres, Quasar Winds:  Quasar Atmospheres, Quasar Winds One geometry unites all the features 85 deg: narrow absorption lines High ionization Broad emission lines Low ionization Fermilab Colloqium 29 October 2003 Components of Quasar Atmospheres:  Components of Quasar Atmospheres High ionization: e.g. CIV, OVI Low ionization: e.g. MgII, Hb. All atomic features now included Thompson thick BAL scatterer must also make Compton hump, Fe-K Fermilab Colloqium 29 October 2003 Putting it all together information filters worked efficiently!:  Putting it all together information filters worked efficiently! hollow cone Elvis M., 2000, ApJ, 545, 63 BALs Polarization no absorption lines NALs BELs WAs Fermilab Colloqium 29 October 2003 Slide40:  Hokusai never saw a live Elephant Not bad – not 100% right – but gets the idea This picture of quasar atmospheres is probably in much the same state: needs physics bones Fermilab Colloqium 29 October 2003 A Quasar Observational Paradigm:  A Quasar Observational Paradigm Disk Winds: tie together all the pieces of the quasar atmosphere Explains features not ‘built in’ BAL covering factor; detachment velocity, Hi ionization BEL blueshifts. Survived tests X-ray absorber outflow v, 2-phase UV/X-ray absorber, pressure balance Makes predictions High ionization BEL, X/UV absorber radii, thickness are equal Creates a research program c.f. Lakatos 1980 Allows tractable physics exploration… Work BACK to origin in accretion disk physics Work OUT to impact on surroundings Can begin to build a ‘low’ theory of quasar atmospheres Fermilab Colloqium 29 October 2003 low theory: 2-phase equilibrium:  low theory: 2-phase equilibrium Krolik, McKee & Tarter 1981, ApJ, 249, 422 Photoionized gas tends to have phases Not really new: Does not work for a static medium so abandoned…. a mistake! Works fine in a wind. dynamic Equilibrium determined solely by: SED & ionization thresholds Should be similar from object to object No need to assume ‘clouds’ Fermilab Colloqium 29 October 2003 low theory: accretion disk physics, II:  low theory: accretion disk physics, II Krongold et al. in preparation new ~106K phase depends critically on SED Nicastro 1999, Reynolds & Fabian 1995 Use absorber (T,x) to determine unseeable EUV SED -> Test models of accretion disk inner edge ill-defined- boundary condition ‘plunging region’ Krolik et al. Reynolds & Fabian 1995 MNRAS 273 116 Fermilab Colloqium 29 October 2003 low theory: Why is the wind thin?:  low theory: Why is the wind thin? Intermediate level 2D theory Wind driven by UV absorption lines c.f. O-star winds, CAK ignore gas pressure 3 Zones: Inner, Middle, Outer 1. Inner: over-ionized Only Compton scattering - insufficient shields gas further out from X-rays = Murray & Chiang `hitchhiking gas’ 2. Middle: UV absorption drives gas  wind escapes 3. Outer: shielded from UV, weak initial push from local disk radiation – wind falls back Risaliti & Elvis 2003, ApJ submitted new density Fermilab Colloqium 29 October 2003 Looking Out: quasars as dust factories:  Looking Out: quasars as dust factories Elvis, Marengo & Karovska, 2002 ApJ, 567, L107 Outflowing BEL gas expands and cools adiabatically BEL adiabats track through dust formation zone of AGB stars Applies to Carbon-rich and Oxygen-rich grains Princeton AGN Physics with the SDSS, 29 July 2003 Outflows rates ~10 Msol/yr at L~1047 erg/s  0.1 Msol/yr of dust assuming dust/gas ratio of Long Period Variables  >107Msol over 108 yr outburst lifetime Metallicity super-solar even in z=6 BELs High Z/Zsol should enhance dust production Larger dust masses likely Looking Out: quasars & starbursts:  Looking Out: quasars & starbursts Elvis, King et al., in preparation Conventionally, starbursts fuel quasar outbursts What if it is the other way around? Princeton AGN Physics with the SDSS, 29 July 2003 All Quasars have winds Quasar wind outflow rates ~1 Msol/yr at L~1046 erg/s  shocks on host galaxy ISM induces starburst Fuels AGN Wind … cycle of AGN/starburst activity? low theory: accretion disk physics, I:  low theory: accretion disk physics, I Wind is sensitive to initial vertical velocity Thickness of wind depends on density & emissivity profile of disk How far can disk deviate from Shakura-Sunyaev r -15/8 law? Constrain viscosity generation, e.g. MRI magneto-rotational instability (Balbus & Hawley) Risaliti et al., in preparation Fermilab Colloqium 29 October 2003 Quasar Atmospheres, Quasar Winds:  Quasar Atmospheres, Quasar Winds Good Observational Paradigm: Quasar Atmospheres are dynamic Thin, rotating, funnel-shaped disk wind Prospects: Use quasar atmospheres for accretion disk physics Dust creation at high z Quasar to Starburst causality Low Theory beginnings: 2 phase medium Line driven winds Fermilab Colloqium 29 October 2003 Postscript: Imaging Quasars:  Postscript: Imaging Quasars At low z sizes are ~0.1 mas Resolvable with planned ground interferometers VLT-I, Ohana Ideal telescopes: Image the wind in space and velocity 5 km-10 km IR 2mm interferometer at ‘Dome C’ in Antartica ½-1km UV space interferometer = NASA ‘Stellar Imager’ Quasar community should push for “Quasi-Stellar Imager” What we really want is to look at quasar atmospheres SOLVE QUASAR ATMOSPHERES No more fancy indirect deductions! Elvis & Karovska, 2002 ApJ, 581, L67 Fermilab Colloqium 29 October 2003

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