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Searches for Black Holes: from Zeldovich and Salpeter to Present Days. A.M.Cherepashchuk (Sternberg Astronomical Institute, Moscow University). Overview of the Problem of Stellar Mass BH. Historical review Standard methods of m BH determination
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Searches for Black Holes:from Zeldovich and Salpeter to Present Days A.M.Cherepashchuk (Sternberg Astronomical Institute, Moscow University)
Overview of the Problem of Stellar Mass BH • Historical review • Standard methods of mBH determination • Results of mBH determination • Distribution of mBH, mNS, • Non-standard methods: a) Determination of i from radial velocity curve (Cyg X-1) b) Determination of mBH from gravitational microlensing effects • Superaccreting BH: SS 433. Supermassive BH
Ya.B.Zeldovich, 1964, Sov.Phys.Dokl., Vol.9, P.195E.E.Salpeter, 1964, Astrophys.J., Vol.140, P.796. Prediction of powerful hard radiation from non-spherical accretion of matter onto a black hole
Gravitational radius 9 mm for the Earth 3 km for the Sun 40 AU for M=2٠109
Era of Space Astronomy began:=10-8 ÷ 10+8 cm • 1962 – first compact X-ray source Sco X-1 located out of Solar System,; -- Rocket experiment, R.Giacconi, Nobel Prize 2002 • 1964 - Ya.B.Zeldovich, E.E.Salpeter, theoretical prediction of the possibility of observations of accreting BH • 1966 - Ya.B.Zeldovich, I D.Novikov, X-rays from accreting BH in binary systems • 1966 - Ya.B.Zeldovich, O.Kh.Guseinov, searches for BH in binary systems • 1967 - I.S.Shklovsky, Sco X-1 is suggested to be an accreting neutron star (NS) in a binary system
1969 - Ya.B.Zeldovich, N.I.Shakura, accretion onto a single non-magnetic NS • 1969 - G.S.Bisnovatyi-Kogan, A.M.Fridman, accretion onto a single magnetic NS • 1971 - V.F.Shwartzman, accretion onto a single BH moving through interstellar medium • 1972 - N.I.Shakura, disk accretion of matter onto a BH in a close binary system; -disk model
1972 - R.A.Sunyaev, theoretical prediction of rapid quasiperiodic variability of X-ray radiation from the inner parts of accretion disks around BH • 1972 - J.Pringle, M.Rees, disk accretion onto NS and BH • 1973 - N.I.Shakura, R.A.Sunyaev, standard -disk theory, X-ray spectrum taking into account comptonization, supercritical accretion onto BH
1973 - I.D.Novikov, K.S.Thorne, disk accretion onto BH taking into account Einstein General Relativity effects: Lx=0.057 c2 for Schwarzschild BH Lx=0.42 c2 for Kerr BH • 1973 - B.Paczynski, A.V.Tutukov, L.R.Yungelson, E.P.J. van den Heuvel, theory of evolution of close binary systems including NS and BH
Theory and Observations Theoretical predictions made in these works were nicely confirmed by further X-ray observations
UHURU Era 1971 – 1972 R.Giaccony ~100 X-ray binary systems
First optical identifications of X-ray binaries, investigations of optical appearances of X-ray binaries 1972 – 1973 L.Webster, P.Murdin (1972) – mass function for Cyg X-1, fv(m)=0.25 N.E.Kurochkin (1972), Her X-1=HZ Her A.M.Cherepashchuk, Yu.N.Efremov, N.E.Kurochkin, R.A.Sunyaev (1972); J.Bahcall, N.Bahcall (1972) – discovery of strong X-ray heating effect in the system HZ Her=Her X-1
V.M.Luytyi, R.A.Sunyaev, A.M.Cherepashchuk (1973, 1974) discovery of ellipticity effect of the optical star in Cyg X-1, estimation of an inclination of the orbital plane and the mass of BH: mx>5.6
X-ray Binaries Up to now ~1000 X-ray binaries have been discovered by instruments aboard many special X-ray observatories, among them Russian MIR-KVANT and GRANAT (R.A.Sunyaev) Several X-ray and Gamma-ray observatories are operating now : CHANDRA, XMM-Newton, INTEGRAL
Stellar Mass BHs About 20 stellar mass BH in X-ray binary systems, as well as several hundreds of supermassive BH in galactic nuclei, have been discovered up to now New branch of astrophysics, Black Hole Demography, developed
Masses of BH and NS in Binary Systems Mass function of an optical star and are masses of a relativistic object and an optical star, respectively.
is an observed value, parameters q, i should be determined from additional observational data: • Light curve:
Rotational broadening of absorption lines in the spectrum of an optical star:
If i is close to 90o: −duration of an X-ray eclipse.
Persistent X-ray binaries (Cyg X-1, LMC X-3, etc.), transient X-ray binaries, X-ray novae (V404 Cyg, XN Mus, etc.) Masses of ~20 stellar mass BH in X-ray binaries have been determined; See, e.g., reviews by P.Charles (1998),T.Shahbaz (1999), J.A.Orosz (2003), A.M.Cherepashchuk (2003).
Constraints on the radii from rapid X-ray variability and high frequency QPO (41 ÷ 450 Hz). See, e.g. recent reviews by McClintockand R.E.Remillard (2003).
Fig.2. Optical spectrum of X-ray Nova Oph 1977 (H1705-250) in quiescent state (Filippenko et al., 1997) and its radial velocity curve
Fig.4. Masses of BH and NS versus masses of their companions in binary systems
Fig.5. Observed distribution of masses of BH and NS versus mass distribution of of WR stars. Open squares correspond to the single mBH obtained from gravitational microlensing effects
In contrast with distribution, mBH and mNS distributions are bimodal: there is a gap in the range (2-4) . Possible explanations of this gap: • Soft equation of state for NS matter and the magneto-rotational mechanism for supernova explosion (K.A.Postnov,M.E.Prokhorov, 2001; G.S.Bisnovatyi-Kogan, 1971)
Postulation of a step function for the supernova explosion energy dependence on the progenitor’s mass (C.L.Fryer, V.Kalogera, 2001); • Enhanced quantum evaporation of BH in some models of multidimension gravity (L.Randall, R.Sundrum, 1999; T.Tanaka, 2003; K.A.Postnov, A.M.Cherepashchuk, 2004)
Non-standard methods of mBH determination Determination of inclination i of theorbital plane from the radial velocity curve: • E.A.Antokhina and A.M.Cherepashchuk, 1997, 2005 • T.Shahbaz, 1998 • M.Abubekerov et al., 2004
Fig.7. Changes of absorption line (Ca I 6439) profiles in the spectrum of an optical star (mv=1 , µ=1, Tv=5000 K, kx=1) in an X-ray binary system
Fig.8. Absorption line Ca I 6439 versus orbital phase in an X-ray binary
Fig.9. Optical star in an X-ray binary (q=mx/mv=1) i=30deg i=90deg
Fig. 10. H absorption line profiles for different values of i and . Orbital Doppler shifts are eliminated.
Fig.11. Ca I 6439 absorption line profiles for different values of i and . Orbital Doppler shifts are eliminated.
Fig.12. Theoretical radial velocity curves for i=30o, 60o, 90o; q=mx/mv=0.2
Fig.13. Radial velocity curve for Cyg X-1 containing 502 observational nights (Abubekerov et al., 2004)
Fig.14. Estimate of i for Cyg X-1 from radial velocity curve: i<44o, mx>9
Fig. 15. Optimal theoretical radial velocity curve for Cyg X-1 for two i: i=35o (solid line) and i=65o (dashed line)
Non-standard methods of mBH determination: gravitational microlensing Gravitational microlensing: A.V.Byalko (1969), B.Paczynski (1986) MACHO, EROS, OGLE, PLANET C.Alcock et al. (1993), C.Alcock et al.(2000): several hundreds of gravitational microlensing effects to ~ ; for M ≈ 0.1 to ≈ 1 month
M=(0.15 – 0.90) M Nature of dark bodies is not quite clear: • Normal dwarf stars (B.V.Komberg et al., 1995; E.J.Kerins, 1997; M.B.Bogdanov,A.M.Cherepashchuk, 1998) • WIMPs (A.V.Gurevich et al., 1996; M.V.Sazhinet al., 1996; A.F.Zakharov, 1999) • Black holes (D.P.Bennett et al., 2002; S.Maoet al., 2002) • Wormholes (A.Einstein, N.Rosen, 1935; M.S.Morris, K.S.Thorne, 1988; A.A.Shatskii, 2003; M.B.Bogdanov, A.M.Cherepashchuk (2002)
MACHO From 321 microlensing effects 28 (i.e. 9%) have the duration to > 140 days (M>0.5 ) Two microlensing effects have to > 1 year and show annual parallax effect
(1) from parallax asymmetry of microlensing light curve → , from rotational curve of the Galaxy → D0l Therefore, M may be determined from equation (1):
MACHO-96-BLG-5, to=965d M= • MCHO-98-BLG-6, to=490d M= • OGLE-1999-BUL-32, to=640d M=(4-13) (D.P.Bennett et al., 2002; S.Mao et al.,2002)
Fig. 16. MACHO-98-BLG-06 microlensing light curve (D.P.Bennett et al., 2002)
Wormhole Possibility to detect a wormhole from microlensing effects (A.A.Shatskii, 2003; M.B.Bogdanov, A.M.Cherepashchuk, 2002) For =2E, circular caustic
1.9E 1.0E 0.0 2.1E Fig. 19. Light curves due to microlensing of a star by a wormhole for different impact parameters: p=2.1E, 1.9E, 1.0E, and 0
Fig.20. Changes of polarization degree during microlensing of a star by a wormhole
Superaccreting Black Hole: SS 433 Superaccreting BH (N.I.Shakura andR.A.Sunyaev, 1973) SS 433 – superaccreting microquasar: v/c≈0.26, pprec=162d.5, porb=13d.082, pnut=6d.28 /yr, ÷ erg/s erg·s-1 See reviews: B.Margon (1984), A.M.Cherepashchuk (1988, 2002) S.N.Fabrika (2004)