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.