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Relativistic Astrophysics: general overview Jean-Pierre Lasota Lecture 1.

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Presentation on theme: "Relativistic Astrophysics: general overview Jean-Pierre Lasota Lecture 1."— Presentation transcript:

1 Relativistic Astrophysics: general overview Jean-Pierre Lasota Lecture 1

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4 For a neutron star P o = 1.41  (Haensel, Lasota & Zdunik 1999)  2GM/c 2 )

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7 black holes cannot form Einstein A, On a stationary system with spherical symmetry consisting of many gravitating masses, 1939 ANNALS OF MATHEMATICS 40: – black holes cannot form black holes must form Oppenheimer, J. R. & Snyder, H., On Continued Gravitational Contraction, Physical Review, 1939, vol. 56, Issue 5, pp – black holes must form

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9 Salgado, Bonazzola, Gourgoulhon, Haensel (1994) Maximum masses of neutron stars. Rhoades & Ruffini 1973) (Nauenberg & Chapline 1973; M max(rot) =1.18 M max Lasota, Abramowicz, Haensel (1996)

10 Richard Tolman

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12 Quasars: Marteen Schmidt C 273: a star-like object with large red-shift. 16%

13 Quasistellar Sources and Gravitational Collapse First Texas Symposium on Relativistic Astrophysics Quasistellar Sources and Gravitational Collapse Austin, December 15-19, 1964

14 The fate of a star and the release of gravitational energy under accretion Doklady Akademii Nauk SSSR 155, (1964) An alternative mechanism of energy emission is examined, in the present note, which is associated with an infall of the external mass in the gravitational field of a collapsing star. Ed Salpeter (1964) Ya. B. Zeldovich

15 Rees 1984: “The idea of infall in a powerful gravitational field as a source of the radiated energy of radiosources was advanced in its most general form by I.S. Shklovsky.” On the Nature of Radio Galaxies Astronomicheskii Zhurnal, Vol. 39, p.591 (1962)

16 The discovery of pulsars (1967), rapidly rotating, strongly magnetized neutron stars changed the attitude of astronomerstowards compact relativistic celestial bodies. The discovery of pulsars (1967), rapidly rotating, strongly magnetized neutron stars changed the attitude of astronomers towards compact relativistic celestial bodies. Jocelyn Bell

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20 Bohdan Paczyński

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23 LISA sensitivity curve LISA sensitivity curve.

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26 M 106 “...good science demands that we seek positive evidence in support of the black hole picture, and watch for credible evidence that the standard picture may not be quite right." (Peebles 2002) M  M=4 1O 7 M 

27 EVIDENCE BY:

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29 Galactic Center: Sgr A * (NAOS/Conica-VLT)

30 Schoedel et al. 2003

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35 QPOs in BH X-ray binaries

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37 red dwarf “hot spot” neutron star or black hole Low-mass X-ray binary (LMXB) ADAF accretion disc

38 Mass function: Minimum mass of the compact object

39 Observed masses of neutron-stars and black-holes

40 t burning > t fall with surface

41 t radiative-cooling > t infall (Advection Dominated Accretion Flows) Quiescent (Low-Mass) X-ray transient

42 Viscous heating: Advective « cooling »: Radiative cooling: F _ = …. (free-free, Compton, synchrotron) Energy conservation: F = F _ + F adv F adv

43 Disc ADAF M quiesc. Log(M). R(P orb )

44 A DIFFERENCE BETWEEN NEUTRON STARS AND BLACK HOLES

45 XMM + Chandra (Lasota 2006)

46 SPIN “PARADIGM” Radio-loudness of AGNs is related to the (high) value of the BH spin. New observational evidence

47 Why two AGN looking the same here have different radio (and high energy) properties?

48 Radio-loudness: Luminosities:

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50 FRIIFRI

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52 Seyfert LINER

53 Elliptical galaxies

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55 At intermediate accretion luminosities, AGNs hosted by giant elliptical galaxies and located in the lower sequence are represented in the sample only by 4 objects. But recently: many radio-quiet galaxies with very massive BH. At intermediate accretion luminosities, AGNs hosted by giant elliptical galaxies and located in the lower sequence are represented in the sample only by 4 objects. But recently: many radio-quiet galaxies with very massive BH. At high accretion luminosities AGN hosted by giant elliptical galaxies are found on both sequences (majority on the lower, “radio-quiet At high accretion luminosities AGN hosted by giant elliptical galaxies are found on both sequences (majority on the lower, “radio-quiet” one) No disc-galaxy hosted AGN on the higher “radio-loud” sequence No disc-galaxy hosted AGN on the higher “radio-loud” sequence

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57 Two types of RQ/RL “bimodality”:  c - intermittency of narrow jet production (two accretion modes)  c - intermittency of narrow jet production (two accretion modes)  c – spin (low for disc galaxies, high for elliptical galaxies) Spin-accretion scenario Slope of the radio-loudness  sequence: accretion rate Normalisation: spin  crit  ~ 10 -3

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59 It is easy to spin-up a black-hole (in an AGN) but difficult to spin it down. That is the problem…


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