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QUASARS AND GALACTIC NUCLEI, A HALF-CENTURY STORY: or the invasion of Massive Black Holes

QUASARS AND GALACTIC NUCLEI, A HALF-CENTURY STORY: or the invasion of Massive Black Holes. Suzy Collin Observatoire de Paris-Meudon. RESEARCH IS NOT A “LONG QUIET RIVER”. THIS PARTICULAR STORY IS FULL OF:. - fruitless observations opening on unexpected discoveries,.

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QUASARS AND GALACTIC NUCLEI, A HALF-CENTURY STORY: or the invasion of Massive Black Holes

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  1. QUASARS AND GALACTIC NUCLEI, A HALF-CENTURY STORY:or the invasion of Massive Black Holes Suzy Collin Observatoire de Paris-Meudon

  2. RESEARCH IS NOT A “LONG QUIET RIVER”.THIS PARTICULAR STORY IS FULL OF: - fruitless observations opening on unexpected discoveries, - come-back of premonitory ideas which were first neglected, - temporary very fashionable but wrong models, - passionate controversies, - misinterpretations responsible for twenty years of stagnation, - wrong arguments for good conclusions, and the opposite… BUT the thousands of papers and nights of the largest telescopes finally opened on a coherent physical model and on a new vision of galaxy evolution

  3. THE FORTIES C. Seyfert (1943) published a paper entitled « Nuclear emission in spiral nebulae » where he studied 6 galaxies with a bright blue nucleus and broad emission lines (up to 8500km/s) NOBODY CARED THE FIFTIES: BIRTH OF RADI0ASTRONOMY Theory of synchrotron radiation (Ginzburg, 1951) Identification of Cyg A and M87(Baade & Minkowski, 1954) Burbidge (1959) realized that an enormous energy is released in these radiogalaxies ~ 10 60-62 ergs = c2 x 106-8 Mo

  4. 1959: BEGINNING OF A CONTROVERSY Woltjer, ApJ 130, p38 The gas emitting the lines in Seyfert galaxies in general should be gravitationally confined by a dense core of about 109 Mo Burbidge2 & Prendergast ApJ 130, p26: The gas emitting the lines in the Seyfert galaxy NGC1068 should be ejected from the nucleus Woltjer was right on wrong arguments (but excusable at this time):he overestimated the mass of gas, and concluded that if the gas is escaping, the nucleus would be emptied very rapidly B2P were right only for NGC 1068, not for other Seyfert galaxies In THIS (S2) galaxy, the gas emitting the lines is partly outflowing

  5. DISCOVERY OF QUASARS Identification of the 3C catalogue: 3C48 is a « blue star » with intense broad but unknown emission lines in its spectrum (Matthews et al, AAS, Dec1960) UNPUBLISHED 3C273 unambiguously identified by moon occultation (Hazard 1962): it is also a blue star with unknown emission lines! breakthrough on Feb 5, 1963 (Schmidt): it is the Balmer spectrum with a « shift towards the red » of 0.16 Note the chance: 3C273 is very luminous, and it has a small shift immediately similar discovery in 3C48 and 2 other objects first Texas symposia, several schools, books… BUT SUBJECT NOT DISCUSSED IN THE IAU GA XII IN 1964

  6. 1965: THE FIRST PROBLEMS APPEARED Greenstein and Schmidt, 1964: discuss the origin of redshift and eliminate a gravitational origin (because the width of the lines should be of the order of the shift) 3C48 and 3C273 are « Quasi Stellar Objects » (quasars) at cosmological distances corresponding to z=0.45 and 0.16 they are very luminous (=1000 galaxies) Harvard catalogue: 3C273 is a variable star (time scale of a week) Dent (1965): the associated radiosource is variable within a year Size << 1pc BEGINNING OF THE REDSHIFT CONTROVERSY

  7. WHAT IS THE SOURCE OF SUCH A BIG ENERGYIN SUCH A SMALL VOLUME? Many mechanisms were invoked: Chain reaction of SN, dense star cluster, “galactic flares”, stellar collisions, supermassive stars but in 1964: independently Salpeter and Zeldovich proposed Energy produced by accretion onto a supermassive black hole, via turbulent transport of angular momentum NOBODY CARED except Lynden-Bell (1969): “Galactic Nuclei as Collapsed Old Quasars”

  8. 1970, VATICAN MEETING ON GALACTIC NUCLEI LyndenBell : accretion on a MBH as the driving energy process. PEOPLE DID NOT CARE Cherchez la femme…

  9. my thesis about Seyfert galaxies:(1965-1968) Andrillat & Souffrin, 1968 - broad lines (all permitted) are emitted by a dense and small region (BLR), contrary to narrow forbidden lines (NLR) which are emitted by a dilute and remote region; it can solve the Woltjer-Burbidge discord. - ionizing mechanism: hard UV and X photons - the broad lines must vary in short time scale; and indeed  This was not believed until the end of seventies; after, there were intensive monitoring of 35 AGN, leading to an unexpected relation R(BLR)/L, thus to M(BH), valid for ALL objects.

  10. GREAT COSMOLOGICAL EXPECTATIONS, GREAT DISAPPOINTMENTS,AND GREAT DISCOVERIES Hope: build a Hubble diagram Mag/z for quasars and deduce the cosmological parameters IMPOSSIBLE! strong cosmological evolution of quasars (Schmidt, 1967) Hope: measure the quantity of HI in the IGM by a L continuum (M. Burbidge, Gunn-Peterson) IMPOSSIBLE! Hydrogen is absent or completely ionized BUT DISCOVERY OF ABSORPTION LINES (Burbidge2, Lynds, 1966) opened a new era for cosmological studies

  11. THE “REDSHIFT CONTROVERSY” “COMPTON CATASTROPHY” (Hoyle, Burbidge & Sandage 1966): (SSC mechanism should suppress rapidly the radio emission) It does not occur if the redshifts are not cosmological PARADOX SOLVED : by relativistic expansion (Rees, 1967) Rees predicted also that “an object moving relativistically in suitable directions may appear to a distant observer to have a transverse velocity much greater than the velocity of light" AND INDEED, A FEW YEARS LATER…

  12. SUPERLUMINIC VELOCITIES (discovered by VLBI in 1970) 1977 1979 1980 3C273 of course, it is not a problem if the redshifts are not cosmological big discussions (ex Texas meeting 1972): phase velocity (christmas tree…), tachions, etc… FINALLY IT IS DUE SIMPLY TO FINITE LIGHT VELOCITY

  13. DEFINITIVE CONFIRMATION THAT JETS AND RADIO-LOBESARE EJECTED FROM GALACTIC NUCLEIAT RELATIVISTIC VELOCITIES NGC 6251, 1978 1 million AL 100000 AL 1 AL

  14. FOR SUPPORTERS OF NON-COSMOLOGICAL REDSHIFTS(Arp, Burbidge, Hoyle, Narlikar…) • Redshifts are “anomalous”, due to an unknown physical law - Quasars are ejected by local AGN (cf. couples of discrepant redshifts, like NGC4319 and Mrk205) - Narrow absorption lines in quasars are due to relativistic gas ejected from quasars and not to intervening intergalactic matter big controversies until the end of the seventies (cf. Copenhagen meeting in 1977) BUT NOW WE KNOW THAT quasars are nuclei of galaxy and the redshift of the host galaxies are measured up to z=2

  15. “Flow chart” of M. Rees, 1977

  16. R. McCrea, 1977 Response of astronomers to a fashionable new idea

  17. FINALLY, THE MBH WON, BUT MAINLY FOR BAD REASONS - Because of the discovery of stellar BHs (like Cygnus X1) - Because very rapid and powerful variations were observed in some objects, but it was due to relativistic boosting! - Because other theories failed somewhere BUT AT LEAST A GOOD ONE A BIG MISTAKE WAS MADE DURING 15 YEARS THE WHOLE FIR TO X-RAY CONTINUUM WAS ATTRIBUTED TO THE SYNCHROTRON MECHANISM (about a power law, and because of radio-source prejudices)

  18. SHIELDS (1978) : THE OPT-UV CONTINUUM IN 3C273 IS EMITTED BY AN ACCRETION DISK AROUND THE BH LOG F “Blue Bump” due to the accretion disk FINALLY THE WHOLE CONTINUUM IS ENTIRELY THERMAL IN RQ QUASARS (AND PARTLY THERMAL IN RL QUASARS), AND IT IS PRODUCED BY THE ACCRETION FLOW

  19. AND AFTER… The eighties: - era of MBHs and accretion disks; - the Unified Scheme. The nineties: - jets and accretion disks unveiled by their X and rays; - dominance of obscured AGN; - the three driving parameters of AGN (M, dotM, i); - omnipresence of MBHs in quiescent galaxies. The millenium: - masses of MBHs, - evolution of galaxies and MBHs. BUT STILL SOME IMPORTANT UNSOLVED PROBLEMS • - Dichotomy of RQ and RL objects (elliptical versus spiral): • Merger and spinning binary BHs? • How are formed very massive BHs at very high redshifts? • How are matter and angular momentum transported at the • parsec scale? • etc…etc…

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