Searches for Black Searches for Black Holes:Holes:

from Zeldovich and from Zeldovich and Salpeter to Present Salpeter to Present

DaysDays

A.M.CherepashchukA.M.Cherepashchuk(Sternberg Astronomical Institute,(Sternberg Astronomical Institute,

Moscow University)Moscow University)

Overview of the Problem of Overview of the Problem of Stellar Mass BH Stellar Mass BH

Historical reviewHistorical review Standard methods of Standard methods of mmBH BH determinationdetermination

Results of Results of mmBHBH determination determination

Distribution of Distribution of mmBHBH, , mmNSNS, , Non-standard methods:Non-standard methods:

a) Determination of a) Determination of i i from radial velocity from radial velocity

curve (Cyg X-1)curve (Cyg X-1)

b) Determination of b) Determination of mmBH BH from gravitational from gravitational

microlensing effectsmicrolensing effects Superaccreting BH: SS 433. Supermassive BHSuperaccreting BH: SS 433. Supermassive BH

Ya.B.Zeldovich, 1964, Ya.B.Zeldovich, 1964, Sov.Phys.Dokl., Vol.9, P.195Sov.Phys.Dokl., Vol.9, P.195

E.E.Salpeter, 1964, E.E.Salpeter, 1964, Astrophys.J., Vol.140, P.796.Astrophys.J., Vol.140, P.796.

Prediction of powerful hard radiation from Prediction of powerful hard radiation from non-spherical accretion of matter onto a non-spherical accretion of matter onto a

black holeblack hole

Gravitational radiusGravitational radius

9 mm for the Earth9 mm for the Earth

3 km for the Sun3 km for the Sun

40 AU for M=240 AU for M=2٠٠10109 9

Era of Space Astronomy began:Era of Space Astronomy began: =10=10-8-8 ÷ 10 ÷ 10+8 +8 cmcm

1962 – first compact X-ray source Sco X-1 1962 – first compact X-ray source Sco X-1 located out of Solar System,; located out of Solar System,;

-- Rocket experiment, -- Rocket experiment, R.GiacconiR.Giacconi, Nobel Prize 2002, Nobel Prize 2002 1964 - 1964 - Ya.B.ZeldovichYa.B.Zeldovich, , E.E.SalpeterE.E.Salpeter, theoretical , theoretical

prediction of the possibility of observations of prediction of the possibility of observations of accreting BHaccreting BH

1966 - 1966 - Ya.B.ZeldovichYa.B.Zeldovich, , I D.NovikovI D.Novikov, X-rays from , X-rays from accreting BH in binary systems accreting BH in binary systems

1966 - 1966 - Ya.B.ZeldovichYa.B.Zeldovich, , O.Kh.GuseinovO.Kh.Guseinov, searches for BH, searches for BH in binary systems in binary systems

1967 - 1967 - I.S.ShklovskyI.S.Shklovsky, Sco X-1 is suggested to be an, Sco X-1 is suggested to be an accreting neutron star (NS) in a binary systemaccreting neutron star (NS) in a binary system

1969 - 1969 - Ya.B.ZeldovichYa.B.Zeldovich, , N.I.ShakuraN.I.Shakura, accretion , accretion onto a single non-magnetic NS onto a single non-magnetic NS

1969 - 1969 - G.S.Bisnovatyi-KoganG.S.Bisnovatyi-Kogan, , A.M.FridmanA.M.Fridman, ,

accretion onto a single magnetic NSaccretion onto a single magnetic NS 1971 - 1971 - V.F.ShwartzmanV.F.Shwartzman, accretion onto a , accretion onto a

single BH moving through interstellar single BH moving through interstellar mediummedium

1972 - 1972 - N.I.ShakuraN.I.Shakura, disk accretion of matter , disk accretion of matter onto a BH in a close binary system; onto a BH in a close binary system;

-disk model-disk model

1972 - 1972 - R.A.SunyaevR.A.Sunyaev, theoretical prediction , theoretical prediction of rapid quasiperiodic of rapid quasiperiodic variability of variability of X-ray radiation from the inner parts X-ray radiation from the inner parts

of accretion disks around BHof accretion disks around BH

1972 - 1972 - J.PringleJ.Pringle, , M.ReesM.Rees, disk accretion onto , disk accretion onto NS and BHNS and BH

1973 - 1973 - N.I.ShakuraN.I.Shakura, , R.A.SunyaevR.A.Sunyaev, standard , standard

-disk theory, X-ray spectrum taking -disk theory, X-ray spectrum taking into account comptonization, into account comptonization, supercritical accretion onto BHsupercritical accretion onto BH

1973 - 1973 - I.D.NovikovI.D.Novikov, , K.S.ThorneK.S.Thorne, disk accretion , disk accretion onto BH taking into account onto BH taking into account Einstein Einstein General Relativity effects: General Relativity effects:

LLxx=0.057 c=0.057 c2 2 for Schwarzschild BH for Schwarzschild BH

LLxx=0.42 c=0.42 c2 2 for Kerr BH for Kerr BH

1973 - 1973 - B.PaczynskiB.Paczynski, , A.V.TutukovA.V.Tutukov, , L.R.YungelsonL.R.Yungelson,,

E.P.J. van den HeuvelE.P.J. van den Heuvel, theory of evolution , theory of evolution of close binary systems including NS of close binary systems including NS and and BH BH

Theory and ObservationsTheory and Observations

Theoretical predictions Theoretical predictions made in these works were made in these works were

nicely confirmed by further X-nicely confirmed by further X-ray observationsray observations

UHURU EraUHURU Era

1971 – 19721971 – 1972

R.GiacconyR.Giaccony

~100 X-ray binary systems~100 X-ray binary systems

First optical identifications of X-ray First optical identifications of X-ray binaries, investigations of optical binaries, investigations of optical

appearances of X-ray binariesappearances of X-ray binaries

1972 – 19731972 – 1973

L.WebsterL.Webster, , P.MurdinP.Murdin (1972) – mass function for (1972) – mass function for Cyg X-1, fCyg X-1, fvv(m)=0.25 (m)=0.25

N.E.Kurochkin N.E.Kurochkin (1972), Her X-1=HZ Her(1972), Her X-1=HZ HerA.M.CherepashchukA.M.Cherepashchuk, , Yu.N.EfremovYu.N.Efremov,,N.E.KurochkinN.E.Kurochkin, , R.A.Sunyaev R.A.Sunyaev (1972); (1972); J.BahcallJ.Bahcall,,N.BahcallN.Bahcall (1972) – discovery of strong X-ray (1972) – discovery of strong X-ray

heating effect in the system HZ Her=Her X-1heating effect in the system HZ Her=Her X-1

V.M.LuytyiV.M.Luytyi, , R.A.SunyaevR.A.Sunyaev, , A.M.Cherepashchuk A.M.Cherepashchuk (1973, 1974)(1973, 1974)

discovery of ellipticity effect of the discovery of ellipticity effect of the optical star in Cyg X-1,optical star in Cyg X-1,

estimation of an inclination of the estimation of an inclination of the orbital plane and the mass of BH:orbital plane and the mass of BH:

mmxx>5.6 >5.6

X-ray BinariesX-ray Binaries

Up to now ~1000 X-ray binaries have Up to now ~1000 X-ray binaries have been discovered by instruments aboard been discovered by instruments aboard

many special X-ray observatories, many special X-ray observatories, among among

them Russian MIR-KVANT and GRANAT them Russian MIR-KVANT and GRANAT ((R.A.SunyaevR.A.Sunyaev))

Several X-ray and Gamma-ray Several X-ray and Gamma-ray observatories are operating now :observatories are operating now :

CHANDRA, XMM-Newton, INTEGRALCHANDRA, XMM-Newton, INTEGRAL

Stellar Mass BHsStellar Mass BHs

About 20 stellar mass BH in X-ray About 20 stellar mass BH in X-ray binary systems, as well as several binary systems, as well as several hundreds of supermassive BH in hundreds of supermassive BH in

galactic nuclei, have been discovered galactic nuclei, have been discovered up to nowup to now

New branch of astrophysics, New branch of astrophysics, Black Hole Demography, Black Hole Demography,

developeddeveloped

Masses of BH and NS in Masses of BH and NS in Binary SystemsBinary Systems

Mass function of an optical starMass function of an optical star

and are masses of a relativistic object andand are masses of a relativistic object and

an optical star, respectively.an optical star, respectively.

2/3)

2e1(PvK

710038.12

)vmxm(

i3

sin3xm

)m(fv

xm vm

)m(fm vx

isin

1)

q

11)(m(fm

32

vx

v

x

m

mq

is an observed value, is an observed value, parametersparameters

q, iq, i should be determined from should be determined from additional observational data: additional observational data:

Light curve:Light curve:

)m(fv

)L,r,q,i,t(l)t(l dd

Rotational broadening of Rotational broadening of absorption lines in the spectrum absorption lines in the spectrum of an optical star:of an optical star:

3/23/1vrot )

q

11(qK462.0isinv

If distance d is known If distance d is known is known too:is known too:

vR

208.1

3/1

2v

2

v q

q1

4

)m(fGP

R

38.0isin

If If i i is close to 90 is close to 90oo::

−−duration of an X-ray eclipse.duration of an X-ray eclipse.

)q,i,(DD xx

Persistent X-ray binaries (Cyg X-1, LMC Persistent X-ray binaries (Cyg X-1, LMC X-3, etc.), transient X-ray binaries, X-ray X-3, etc.), transient X-ray binaries, X-ray

novae (V404 Cyg, XN Mus, etc.) novae (V404 Cyg, XN Mus, etc.)

Masses of ~20 stellar mass BH Masses of ~20 stellar mass BH in X-ray binaries have been in X-ray binaries have been

determined;determined;

See, e.g., reviews by See, e.g., reviews by P.Charles P.Charles (1998),(1998), T.Shahbaz T.Shahbaz (1999), (1999),

J.A.OroszJ.A.Orosz (2003), (2003), A.M.Cherepashchuk A.M.Cherepashchuk (2003).(2003).

Constraints on the radii Constraints on the radii

from rapid X-ray variability and high from rapid X-ray variability and high frequency QPOfrequency QPO

(41 ÷ 450 Hz).(41 ÷ 450 Hz).

See, e.g. recent reviews by See, e.g. recent reviews by McClintockMcClintock and R.E.Remillard and R.E.Remillard

(2003).(2003).

Fig.1. Fig.1. Moving X-ray binaryMoving X-ray binary

Fig.2. Optical spectrum of X-ray Nova Oph 1977 Fig.2. Optical spectrum of X-ray Nova Oph 1977 (H1705-250) in quiescent state (Filippenko et al., (H1705-250) in quiescent state (Filippenko et al.,

1997) and its radial velocity curve 1997) and its radial velocity curve

Fig.3. Optical light curve of Cyg X-1 (Lytyi et Fig.3. Optical light curve of Cyg X-1 (Lytyi et al., 1973) al., 1973)

Fig.4. Masses of BH and NS versus masses Fig.4. Masses of BH and NS versus masses of their companions in binary systems of their companions in binary systems

Fig.5. Observed distribution of masses of BH and Fig.5. Observed distribution of masses of BH and NS versus mass distribution of of WR stars. NS versus mass distribution of of WR stars. Open squares correspond to the single mOpen squares correspond to the single mBH BH

obtained from gravitational microlensing effectsobtained from gravitational microlensing effects

fcom

In contrast with distribution,In contrast with distribution,

mmBH BH and m and mNSNS distributions are bimodal: distributions are bimodal:

there is a gap in the range (2-4) .there is a gap in the range (2-4) .

Possible explanations of this gap:Possible explanations of this gap:

Soft equation of state for NS matter and Soft equation of state for NS matter and the magneto-rotational mechanism for the magneto-rotational mechanism for supernova explosion (supernova explosion (K.A.Postnov,K.A.Postnov, M.E.ProkhorovM.E.Prokhorov, 2001; , 2001; G.S.Bisnovatyi-KoganG.S.Bisnovatyi-Kogan, , 1971)1971)

Postulation of a step function for the Postulation of a step function for the supernova explosion energy supernova explosion energy dependence on the progenitor’s mass dependence on the progenitor’s mass ((C.L.FryerC.L.Fryer, , V.KalogeraV.Kalogera, 2001);, 2001);

Enhanced quantum evaporation of BH Enhanced quantum evaporation of BH in some models of multidimension in some models of multidimension gravity (gravity (L.RandallL.Randall, , R.SundrumR.Sundrum, 1999; , 1999; T.TanakaT.Tanaka, 2003; , 2003; K.A.PostnovK.A.Postnov, , A.M.CherepashchukA.M.Cherepashchuk, 2004), 2004)

Non-standard methods of mNon-standard methods of mBH BH

determinationdetermination

Determination of inclination Determination of inclination i i of theof the orbital orbital plane from the radial velocity curve:plane from the radial velocity curve:

E.A.Antokhina and A.M.CherepashchukE.A.Antokhina and A.M.Cherepashchuk, , 1997, 20051997, 2005

T.ShahbazT.Shahbaz, 1998, 1998 M.Abubekerov et al.M.Abubekerov et al., 2004, 2004

Fig.6. Moving optical star in X-ray binaryFig.6. Moving optical star in X-ray binary

Fig.7. Changes of absorption line (Ca I Fig.7. Changes of absorption line (Ca I 6439) 6439) profiles in the spectrum of an optical star profiles in the spectrum of an optical star (m (mvv=1 , µ=1, T=1 , µ=1, Tvv=5000 K, k=5000 K, kxx=1) in an =1) in an X-ray binary system X-ray binary system

Fig.8. Absorption line Ca I Fig.8. Absorption line Ca I 6439 versus orbital 6439 versus orbital phase in an X-ray binary phase in an X-ray binary

Fig.9. Optical star in an X-ray Fig.9. Optical star in an X-ray binary (q=mbinary (q=mxx/m/mvv=1)=1)

i=90degi=90deg i=30degi=30deg

Fig. 10. HFig. 10. H absorption line profiles for different absorption line profiles for different values of values of i i and and . Orbital . Orbital

Doppler Doppler shifts are eliminated. shifts are eliminated.

Fig.11. Ca I Fig.11. Ca I 6439 absorption line profiles for 6439 absorption line profiles for different values of different values of i i and and . .

Orbital Orbital Doppler shifts are eliminated. Doppler shifts are eliminated.

Fig.12. Theoretical radial velocity curves Fig.12. Theoretical radial velocity curves for i=30 for i=30oo, 60, 60oo, 90, 90oo; q=m; q=mxx/m/mvv=0.2=0.2

Fig.13. Radial velocity curve for Cyg X-1 containingFig.13. Radial velocity curve for Cyg X-1 containing

502 observational nights (Abubekerov et al., 2004)502 observational nights (Abubekerov et al., 2004)

Fig.14. Estimate of i for Cyg X-1 from radial Fig.14. Estimate of i for Cyg X-1 from radial

velocity curve: i<44velocity curve: i<44oo, m, mxx>9 >9

Fig. 15. Optimal theoretical radial velocity curve Fig. 15. Optimal theoretical radial velocity curve

for Cyg X-1 for two i:for Cyg X-1 for two i:

i=35i=35oo (solid line) and i=65 (solid line) and i=65o o (dashed line)(dashed line)

Non-standard methods of Non-standard methods of mmBHBH determination: determination:

gravitational microlensinggravitational microlensing

Gravitational microlensing:Gravitational microlensing:

A.V.ByalkoA.V.Byalko (1969), (1969), B.PaczynskiB.Paczynski (1986) (1986)

MACHO, EROS, OGLE, PLANETMACHO, EROS, OGLE, PLANET

C.Alcock et al.C.Alcock et al. (1993), (1993), C.Alcock et al.(C.Alcock et al.(2000):2000):

several hundreds of gravitational several hundreds of gravitational microlensing effectsmicrolensing effects

tto o ~ ; for M ~ ; for M ≈ 0.1 t≈ 0.1 to o ≈ 1 month≈ 1 monthM

M=(0.15 – 0.90) MM=(0.15 – 0.90) M

Nature of dark bodies is not quite clear:Nature of dark bodies is not quite clear: Normal dwarf stars (Normal dwarf stars (B.V.Komberg et al.B.V.Komberg et al., 1995; , 1995;

E.J.KerinsE.J.Kerins, 1997; , 1997; M.B.Bogdanov,M.B.Bogdanov, A.M.CherepashchukA.M.Cherepashchuk, 1998), 1998)

WIMPs (WIMPs (A.V.Gurevich et al.A.V.Gurevich et al., 1996; , 1996; M.V.SazhinM.V.Sazhin et al.et al., 1996; , 1996; A.F.ZakharovA.F.Zakharov, 1999), 1999)

Black holes (Black holes (D.P.Bennett et al.D.P.Bennett et al., 2002; , 2002; S.MaoS.Mao et al.et al., 2002), 2002)

Wormholes (Wormholes (A.Einstein, N.RosenA.Einstein, N.Rosen, 1935; , 1935; M.S.Morris, K.S.ThorneM.S.Morris, K.S.Thorne, 1988; , 1988; A.A.ShatskiiA.A.Shatskii, , 2003; 2003; M.B.Bogdanov, A.M.CherepashchukM.B.Bogdanov, A.M.Cherepashchuk (2002)(2002)

MACHOMACHO

From 321 microlensing effects 28 (i.e. From 321 microlensing effects 28 (i.e. 9%) have the duration t9%) have the duration too > 140 days > 140 days

(M>0.5 )(M>0.5 )

Two microlensing effects have tTwo microlensing effects have to o > 1 year > 1 year

and show annual parallax effectand show annual parallax effect

s0

l0s0l0E0 D

)DD(GMD

cv

4

v

R2t

(1)(1)

from parallax asymmetry of microlensing from parallax asymmetry of microlensing light curvelight curve → , → ,

from rotational curve of the Galaxy → Dfrom rotational curve of the Galaxy → D0l0l

Therefore, M may be determined from Therefore, M may be determined from equation (1):equation (1):

v

MACHO-96-BLG-5, tMACHO-96-BLG-5, too=965=965dd

M= M= MCHO-98-BLG-6MCHO-98-BLG-6, , ttoo=490=490dd

M= M= OGLE-1999-BUL-32, tOGLE-1999-BUL-32, too=640=640dd

M=(4-13) M=(4-13)

((D.P.Bennett et al.D.P.Bennett et al., 2002; , 2002;

S.Mao et al.S.Mao et al.,2002),2002)

1036

736

Fig. 16. MACHO-98-BLG-06 microlensing lightFig. 16. MACHO-98-BLG-06 microlensing light

curve (D.P.Bennett et al., 2002)curve (D.P.Bennett et al., 2002)

WormholeWormhole

Possibility to detect a wormhole from Possibility to detect a wormhole from microlensing effectsmicrolensing effects

((A.A.ShatskiiA.A.Shatskii, 2003;, 2003;

M.B.Bogdanov, A.M.CherepashchukM.B.Bogdanov, A.M.Cherepashchuk, , 2002)2002)

For For =2=2EE,,

circular causticcircular caustic

Fig. 19. Light curves due to microlensing of a Fig. 19. Light curves due to microlensing of a star by a wormhole for different impact star by a wormhole for different impact

parameters: p=2.1parameters: p=2.1EE, 1.9, 1.9EE, 1.0, 1.0EE, and 0, and 0

2.12.1EE

1.91.9EE 1.01.0EE 0.00.0

Fig.20. Changes of polarization degreeFig.20. Changes of polarization degree

during microlensing of a star by aduring microlensing of a star by a

wormholewormhole

Superaccreting Black Hole: Superaccreting Black Hole: SS 433 SS 433

Superaccreting BH (Superaccreting BH (N.I.Shakura andN.I.Shakura and R.A.SunyaevR.A.Sunyaev, 1973), 1973)

SS 433 – superaccreting microquasar:SS 433 – superaccreting microquasar:

v/cv/c≈0.26, p≈0.26, pprecprec=162=162dd.5, p.5, porborb=13=13dd.082, p.082, pnutnut=6=6dd.28.28 /yr, /yr, ÷ ÷ erg/serg/s erg·serg·s-1-1

See reviews: See reviews: B.MargonB.Margon (1984), (1984), A.M.CherepashchukA.M.Cherepashchuk (1988, 2002) (1988, 2002)S.N.FabrikaS.N.Fabrika (2004) (2004)

410M

39bol

disk 10L 4010392 102/vM

SS 433SS 433

Photospheric absorption spectrum of the Photospheric absorption spectrum of the normal star has been discoverednormal star has been discovered

((D.R.Gies et al.D.R.Gies et al., 2002;, 2002;A.M.Cherepashchuk et al.A.M.Cherepashchuk et al., 2004), 2004)

The relativistic object may be suggested The relativistic object may be suggested to be a BHto be a BH

((D.R.Gies et al.D.R.Gies et al., 2002; , 2002; A.M.Cherepashchuk et al.A.M.Cherepashchuk et al., 2004;, 2004;

T.C.Hillwig et al.T.C.Hillwig et al., 2004), 2004)

Fig.21. Shape of orbital V light curves of SS 433Fig.21. Shape of orbital V light curves of SS 433

as a function of precession phases as a function of precession phases

INTEGRAL observationsINTEGRAL observations

Hard X-ray radiation from SS 433 was discovered:Hard X-ray radiation from SS 433 was discovered:

((A.M.Cherepashchuk, R.A.Sunyaev, E.V.Seifina et al.A.M.Cherepashchuk, R.A.Sunyaev, E.V.Seifina et al., , 2003)2003)

LLxx(18-60 keV)(18-60 keV)≈4·10≈4·1035 35 erg·serg·s-1-1

LLxx(60-120 keV)≈2·10(60-120 keV)≈2·103535 erg·s erg·s-1-1

which is ~10 % of the soft X-ray jet luminosity.which is ~10 % of the soft X-ray jet luminosity.

Maximum of the accretion disk luminosity lies in Maximum of the accretion disk luminosity lies in the optical-ultraviolet range.the optical-ultraviolet range.

Fig.22. Precessional and eclipsing hard X-ray (25-50 keV) Fig.22. Precessional and eclipsing hard X-ray (25-50 keV)

variability of SS 433 (variability of SS 433 (A.M.CherepashchukA.M.Cherepashchuk, ,

R.A.SunyaevR.A.Sunyaev, , S.N.Fabrica et al.S.N.Fabrica et al., 2004), 2004)

Some remarks about Some remarks about supermassive black holes in supermassive black holes in

galactic nucleigalactic nuclei

Ya.B.Zeldovich, I.D.NovikovYa.B.Zeldovich, I.D.Novikov (1964): (1964):

first estimate of mfirst estimate of mBHBH for QSO for QSO

Investigations of motions of gas and Investigations of motions of gas and stars in the nuclei of galaxiesstars in the nuclei of galaxies

>300 BH with m>300 BH with mBHBH≈ 10≈ 1066 ÷ 10 ÷ 1099

BH DemographyBH Demography

MMBHBH≈ 0.0012 ≈ 0.0012

((R.J.McLureR.J.McLure, , J.S.DunlopJ.S.Dunlop, 2002), 2002) MMBH ~ BH ~

((S.Tremaine et al.S.Tremaine et al., 2002), 2002) MMBH ~ BH ~

((M.Baes et al.M.Baes et al., 2003), 2003)

A.S.Ilyin, K.P.Zybin, A.V.GurevichA.S.Ilyin, K.P.Zybin, A.V.Gurevich (2004) (2004)

Halo Halo → cusp → BH→ cusp → BH

05.095.0elgBuM

4elgBu

27.1HaloM

CorrelationsCorrelations

between and Mbetween and MBHBH

between between BulgeBulge and M and MBHBH..

((A.V.Zasov, L.N.Petrochenko,A.V.Zasov, L.N.Petrochenko, A.M.CherepashchukA.M.Cherepashchuk, 2004), 2004)

For the same , MFor the same , MBH BH is higher for is higher for

early type galaxies (S0 – Sab) havingearly type galaxies (S0 – Sab) having

more massive bulges.more massive bulges.

rotmaxV

rotmaxV

Fig.23. Diagram: Maximal rotational velocityFig.23. Diagram: Maximal rotational velocity

VVmm versus M versus MBH BH for galaxies. Open circles for galaxies. Open circles

correspond to the early type galaxiescorrespond to the early type galaxies

S0 – Sab with more massive bulgesS0 – Sab with more massive bulges

Future progressFuture progress Distance determinations for X-ray binaries: GAIA etc. Distance determinations for X-ray binaries: GAIA etc.

Improving mImproving mBHBH values. values. Direct measurements of the event horizon radius: Direct measurements of the event horizon radius:

Space X-ray Interferometer.Space X-ray Interferometer. Detection of gravitational waves from merging BH in Detection of gravitational waves from merging BH in

close binary systems: LIGA, VIRGO, LISA etc.close binary systems: LIGA, VIRGO, LISA etc. X-ray andX-ray and-ray investigations of accreting BHs with -ray investigations of accreting BHs with

space observatories of the next generation: space observatories of the next generation: SPECTRX-Gamma etc.SPECTRX-Gamma etc.

Routine accumulation of data on mRoutine accumulation of data on mBHBH , m , mNSNS and and

statistical comparison of the properties of NSs and statistical comparison of the properties of NSs and BHs.BHs.