1 / 78

ASTROPHYSICAL BLACK HOLES

ASTROPHYSICAL BLACK HOLES. SOME HISTORY. Escape velocity v u 2 = 2 GM/R. Earth v esc = 11 km/s Jupiter v esc = 60 km/s Sun v esc = 600 km/s Moon v esc = 2 km/s. r = 2 G M/v esc 2. J. Michel P. Laplace r(v esc =c) = ?. r g = 2 G M/c 2.

fern
Download Presentation

ASTROPHYSICAL BLACK HOLES

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. ASTROPHYSICAL BLACK HOLES

  2. SOME HISTORY Escape velocity vu2 = 2 GM/R Earth vesc = 11 km/s Jupiter vesc = 60 km/s Sun vesc = 600 km/s Moon vesc = 2 km/s r = 2 G M/vesc2 J. Michel P. Laplacer(vesc=c) = ?

  3. rg = 2 G M/c2 rggravitational radius Schwarzshild’s radius (rS) radius of event horizon rg = 3 M/MSUN km Term „black hole” introduced by J. Wheeler in 1964 For neutron star: rg≈ 4.2 km rNS≈ 10 km

  4. From 7 orbits: MBH = (3.7 ± 0.2) x 106 MSUN (Ghez & al., 2005) Star S0-16 approaches the focus of the orbit to a distance of ~45 A.U. (~ 6 light hours or ~ 600 RS )

  5. From new analysis of orbit of S0-2 (astrometry & RVs from Keck 10 m): MBH = (4.5 ± 0.4) x 106 MSUN independently D = 8.4 ± 0.4 kpc (Ghez & al., 2008)

  6. HOW ARE BLACK HOLES CREATED ? They are evolutionary remnants of massive stars

  7. FINAL PRODUCTS OF STELLAR EVOLUTION ●low mass stars (M ≤ 10 MSUN) WHITE DWARFS M ~ 0.2 ÷ 1.3 MSUN, R ~ 10 000 km ●massive stars (10 MSUN≤ M ≤ 20 MSUN) NEUTRON STARS M ~ 1 ÷ 2 MSUN, R ~ 10 km ●very massive stars (M ≥20 MSUN) BLACK HOLES M ≥ 3 MSUN observedM ~ 4 ÷ 33 MSUN

  8. X-RAY SKY (UHURU, 1977)

  9. Black holes can grow up i.e. increase their masses. This is done by attracting the matter from the neighbourhood (BH acts as a „vacuum cleaner”) or by mergers. In this way intermediate mass BHs (thousands solar masses) and then supermassive black holes (millions to billions solar masses) are created.

  10. 3 CLASSES OF BHs ● STELLAR MASS BHs ● INTERMEDIATE MASS BHs ● SUPERMASSIVE BHs

  11. HOW DO WE KNOW THAT BLACK HOLES ARE THERE ?

  12. ALL THESE ARGUMENTS PROVIDE ONLY CIRCUMSTANTIAL EVIDENCE HARD EVIDENCE COMES ONLY FROM DYNAMICAL ESTIMATE OF THE MASS OF THE COMPACT OBJECT

  13. UPPER MASS LIMITforNSs ●THEORY ●OPPENHEIMER-VOLKOFF MASS: MOV≈ 1.4÷ 2.7 MSUNdepending on the equation of state FOR EXTREME EQUATION OF STATE :P=ρc2 (assuming only GR and causality): MOV≈ 3.2 MSUNfor non-rotating NS MOV≈ 3.9 MSUNfor maximally rotating NS

  14. ●OBSERVATIONS ●BINARY RADIO PULSARS MNS≈ 1.33 ÷ 1.44 MSUN (until recently) ●BINARY X-RAY PULSARS MNS≈ 1.1 ÷ 1.9 MSUN(large errors)

  15. NEW DETERMINATIONS OF NS MASSES ●PSR J0737-3039B M = 1.250 ± 0.005 MSUN (Lyne & al., 2004) ●PSR J1903+0327 M = 1.67± 0.01 MSUN (Champion & al., 2008)

  16. NGC 6440B • After ~1 year timing this pulsar, we have obtained a good measurement of the rate of advance of periastron. If fully relativistic, this implies a total system mass of ~2.92 ± 0.25 solar masses! • The companion has likely only ~0.1 solar masses. Median of probability for pulsar mass is 2.74 solar masses. • There is a 99% probability of mass being larger than 2 solar masses, 0.1% probability of having a “normal” mass. • Is this a super-massive neutron star? From: Freire et al. (2008a), ApJ 675, 670

  17. PSR J1903+0327 Freire, 2009

  18. CONFIRMED BHs IN XRBs Name PorbOpt. Sp.X-RCMBH/Msun Cyg X-1 5d6O9.7 IabpersμQ20 ± 5 LMC X-3 1d70 B3 V pers6 ÷ 9 LMC X-1 4d22 O7-9 III pers10.9±1.4 SS 433 13d1~ A7 IbpersμQ16 ± 3 LS 5039 3d906O7f V pers μQ2.7 ÷ 5.0 XTE J1819-254 2d817B9 III T μQ6.8 ÷ 7.4 GX 339-4 1d76 F8-G2 III RT μQ≥ 6 GRO J0422+32 5h09 M2 V T 4 ± 1 A 0620-007h75 K4 V RT 11 ± 2 GRS 1009-45 6h96 K8 V T 4.4 ÷ 4.7 XTE J1118+480 4h1 K7-M0 V T 8.5 ± 0.6 GS 1124-68410h4 K0-5 V T 7.0 ± 0.6

  19. CONFIRMED BHs IN XRBs (cont.) Name PorbOpt. Sp.X-RCMBH/Msun GS 1354-645 2d54G0-5 IIIT>7.8 ± 0.5 4U 1543-47 1d12A2 VRT8.5 ÷ 10.4 XTE J1550-564 1d55K3 IIIRT μQ10.5 ± 1.0 XTE J1650-500 7h63K4 V T μQ4.0 ÷ 7.3 GRO J1655-40 2d62F3-6 IVRT μQ6.3 ± 0.5 4U 1705-250 12h54K5 V T5.7 ÷ 7.9 GRO J1719-24 14h7M0-5 V T> 4.9 XTE J1859+226 9h16~G5 T 8 ÷ 10 GRS 1915+105 33d5K-M IIIRT μQ14 ± 4.4 GS 2000+25 8h26K5 VT 7.1 ÷ 7.8 GS 2023+338 6d46K0 IV RT10.0 ÷ 13.4

  20. INTERMEDIATE MASS BHs ●range of masses:~ 102÷ 104 MSUN TWO CLASSES OF CANDIDATES: ●ULXs ●globular clusters

  21. GLOBULAR CLUSTERS Do some of them contain IMBHs ? Some of them, probably, yes. How many – it remains an open question.

  22. Brightness profiles rc/rh clusters with IMBHs have expanded cores (rc/rh > 0.1)

  23. Trenti (2006) considered a sample of 57 old globular clusters For at least half of them, he foundrc/rh≥ 0.2 IMBHsnecessary!

  24. Velocity dispersion correlates well with MBH(IMBH or SMBH)

  25. Gebhardt et al., 2002

  26. STRONGEST CANDIDATES ●[G1 MBH~ 20 000 MSUN Gebhardt et al., 2005] ●M15MBH~ 2 000 MSUNGerssen et al., 2003 ●ω CenMBH~ 50 000 MSUNNoyola et al., 2006

  27. Are ULXsBH binaries (IMBH binaries) ? Some of them – yes! The term „ULXs” is probably a sort of an umbrella covering several different classes of objects One of them is, most likely, a class of XRBs containing IMBHs

  28. M 82 X-1 Lx≈ (2.4 ÷16) x 1040erg/s(if Lx = LEd, Mx = 150 ÷ 1000 Msun) QPOs:0.054 & 0.114 Hz Mx~200 ÷ 5000 Msun probably accreting from a ~ 25 Msun giant filling its Roche lobe Porb ≈ 62 d In dense stellar cluster MGG-11,7 ÷ 12 Myrold (Patruno et al., 2006)

  29. SUPERMASSIVE BHs ●range of masses:3x105÷ 6x1010 MSUN

  30. DIFFERENT WAYS OF DETERMINING MBH ●Kepler’s law ● individual stars ● water masers ● MBH–Mbulge relation ● „reverberation” (also based on Kepler’s law) ●„variance” (X-ray variability)

More Related