Black Holes in Astrophysics

Plenary review talk I gave the Annual Meeting of the Brazilian Astronomical Society. Aug 31st 2016, Ribeirão Preto.

Some of the results presented are not yet available for public release.

Transcript

1. Rodrigo Nemmen IAG USP Black Holes in Astrophysics Aug. 31st 2016
 Reunião SAB
 Ribeirão Preto M. Weiss, CfA
2. Collaborators R. Nemmen G. Soares F. Cafardo R. Menezes H. Gubolin I. Almeida A. Vemado Sasha Tchekhovskoy Berkeley Vasilis Paschalidis Princeton Jack Hewitt UNF Markos Georganopoulos, Eileen Meyer UMBC Neil Gehrels, Sylvain Guiriec, Francesco Tombesi NASA GSFC Thaisa Storchi Bergmann, Jaderson Schimoia UFRGS Elisabete de Gouveia dal Pino USP Mike Brotherton UWyoming Mike Eracleous Penn State Rita Sambruna NASA
3. Black holes are the most perfect macroscopic objects in the universe R. Nemmen No-hair theorem: fully described by mass M, spin a (Kerr metric) J = a GM2/c 0  |a|  1 Event horizon: Once inside, nothing escapes Made only of spacetime warpage RS = 2GM c2
4. Black holes are the most perfect macroscopic objects in the universe R. Nemmen No-hair theorem: fully described by mass M, spin a (Kerr metric) J = a GM2/c 0  |a|  1 Event horizon: Once inside, nothing escapes Made only of spacetime warpage RS = 2GM c2
5. Black holes are the most perfect macroscopic objects in the universe No-hair theorem: fully described by mass M, spin a (Kerr metric) J = a GM2/c 0  |a|  1 Event horizon: Once inside, nothing escapes Made only of spacetime warpage RS = 2GM c2 R. Nemmen
6. Black holes are the most perfect macroscopic objects in the universe No-hair theorem: fully described by mass M, spin a (Kerr metric) J = a GM2/c 0  |a|  1 Event horizon: Once inside, nothing escapes Made only of spacetime warpage RS = 2GM c2 R. Nemmen
7. Black holes are the most perfect macroscopic objects in the universe R. Nemmen No-hair theorem: fully described by mass M, spin a (Kerr metric) J = a GM2/c 0  |a|  1 Event horizon: Once inside, nothing escapes Made only of spacetime warpage RS = 2GM c2
8. Black holes are the most perfect macroscopic objects in the universe R. Nemmen No-hair theorem: fully described by mass M, spin a (Kerr metric) J = a GM2/c 0  |a|  1 Event horizon: Once inside, nothing escapes Made only of spacetime warpage RS = 2GM c2
9. A black hole in vacuum is quite boring Hawking evaporation takes >1067 years (3 MSun) Why are black holes so interesting for astrophysics?
10. Supermassive 106-1010 solar masses one in every galactic nucleus 5-30 solar masses ~107 per galaxy Stellar black holes ~1 Mpc ~100 kpc Active galactic nuclei Quasars Radio galaxies black holes Gamma- ray bursts Microquasars 1 pc = 3×1013 km
11. https://xkcd.com/681/
13. VENUS MERCURY EARTH 6,379 KM To sun, far down
14. sun MERCURY
15. sun MERCURY Radii of objects not to scale 100x deeper Mercury depth gravity well To black hole, very VERY far down
16. sun VENUS MERCURY EARTH 6,379 KM To sun, far down Radii of objects not to scale 100x deeper Mercury depth gravity well To black hole, very VERY far down
17. ç depth gravity well ç Black holes have deep, relativistic gravity wells ç BLACK HOLE sun 106x deeper
18. ç depth gravity well ç Black holes have deep, relativistic gravity wells ç BLACK HOLE sun 106x deeper
19. ç depth gravity well ç Black holes have deep, relativistic gravity wells ç BLACK HOLE sun 106x deeper
20. Credit: ESO Radiative efficiency: Deep gravity wells → BH accretion disks are the most efficient radiators in the universe ⌘ rad = Erad out Egas in = 10 40% 100x more efficient than nuclear fusion!
21. Credit: ESO Radiative efficiency: Deep gravity wells → BH accretion disks are the most efficient radiators in the universe ⌘ rad = Erad out Egas in = 10 40% 100x more efficient than nuclear fusion!
22. Black holes spin → spin generates spacetime whirlwind (non-Newtonian effect) Huge energy stored in rotating spacetime black hole
23. Huge energy stored in rotating spacetime Black holes spin → spin generates spacetime whirlwind (non-Newtonian effect) spinning BH https://www.youtube.com/watch?v=9MHuhcFQsBg
24. Huge energy stored in rotating spacetime Black holes spin → spin generates spacetime whirlwind (non-Newtonian effect) spinning BH https://www.youtube.com/watch?v=9MHuhcFQsBg
25. Black hole outflows and jets from Kerr spacetime + accretion + B Semenov+04, Science possibilities remain to be better explored in future simula- tions of accretion flows. Interestingly enough, s is similar to the dispersion of s values obtained in the hydrodynamic RIAF simulations of Yuan, Wu & Bu (2012); Bu et al. (2013) for a range of initial conditions. Range of black hole spins and/or magnetic flux threading the horizon – If powerful jets are produced via the BZ mecha- nism then the two fundamental parameters that regulate the jet power are the black hole spin a and the magnetic flux h threading the horizon, besides the mass (Blandford & Znajek 1977; Semenov, Dyadechkin & Punsly 2004): Pjet / ⇠ ✓ a h M ◆2 ; (9) i.e., a and h are degenerate to some extent (cf. Jet power Blandford & Znajek 77; Komissarov+; Nemmen+07; Tchekhovskoy+ spin magnetic flux Blandford-Znajek mechanism: magnetic flux tube spinning black hole ergosphere ⇠ a2 ˙ Mc2 ⊵
26. Black hole outflows and jets from Kerr spacetime + accretion + B Semenov+04, Science possibilities remain to be better explored in future simula- tions of accretion flows. Interestingly enough, s is similar to the dispersion of s values obtained in the hydrodynamic RIAF simulations of Yuan, Wu & Bu (2012); Bu et al. (2013) for a range of initial conditions. Range of black hole spins and/or magnetic flux threading the horizon – If powerful jets are produced via the BZ mecha- nism then the two fundamental parameters that regulate the jet power are the black hole spin a and the magnetic flux h threading the horizon, besides the mass (Blandford & Znajek 1977; Semenov, Dyadechkin & Punsly 2004): Pjet / ⇠ ✓ a h M ◆2 ; (9) i.e., a and h are degenerate to some extent (cf. Jet power Blandford & Znajek 77; Komissarov+; Nemmen+07; Tchekhovskoy+ spin magnetic flux Blandford-Znajek mechanism: ⇠ a2 ˙ Mc2 ⊵
27. Gamma-ray bursts 3C 31 4 I.F. Mirabel Fig. 1.2 The British journal Nature announced on July 16, 1992 the discovery of a microquasar in the Galactic center region [22]. The image shows the synchrotron emission at a radio wavelength of 6 cm produced by relativistic particles jets ejected from some tens of kilometers to light years Black hole binaries (microquasars) ~1 pc 1E1740.7-2942 ~1 Mpc ~100 kpc Active galactic nuclei ~10-4 pc? Tidal disruption events
28. Energy release from supermassive BHs impact large scale structure formation (“AGN feedback”) galaxy time
29. Energy release from supermassive BHs impact large scale structure formation (“AGN feedback”) <10-4 pc galaxy time SMBH
30. Energy release from supermassive BHs impact large scale structure formation (“AGN feedback”) time BH accretion
31. Energy release from supermassive BHs impact large scale structure formation (“AGN feedback”) time outflows
32. Energy release from supermassive BHs impact large scale structure formation (“AGN feedback”) time
33. 10 Mpc Fabian 12 ARAA; Tombesi+15 Nature; Cheung +16 Nature; Vogelsberger+14 Nature Energy release from supermassive BHs impact large scale structure formation (“AGN feedback”) “BH explosions” in the simulation
34. 10 Mpc Fabian 12 ARAA; Tombesi+15 Nature; Cheung +16 Nature; Vogelsberger+14 Nature Energy release from supermassive BHs impact large scale structure formation (“AGN feedback”) “BH explosions” in the simulation
35. “HR-diagram” for BHs: stellar BHs change states in Δt ~ days; AGNs in Δt ≳105 years? phase, the behavior of by infrared and radio so begins to change. mission drops almost tate transition begins a change in the jet ty andmagneticfield) ck hole. mission begins to vary lly, showing oscilla- vents superposed on ne (8, 15). At a cer- are one or more large h can be two or more tude more luminous s existing, steadier jet e. In several notable lution radio observa- flares have directly r even x-ray–emitting way from the central 17), which can be ced back to the time hard transition ing a range of can occur (eve generally occu few percent o nosity (24). In never been co in any BHXR low 1% Eddin source reache state again, w same spectral istics as the in has reappeare disc wind is g state, the sou typically belo of all-sky or re and are obser until their next phases are not ever, for it is that—without X-ray spectrum X-ray luminosity SOFT HARD A B C D E F oles Fender & Belloni 12 Science X-ray luminosity During this phase, the behavior of the jet, revealed by infrared and radio observations, also begins to change. hard transition, although also ing a range of luminosities at w can occur (even in the same s X-ray spectrum SOFT HARD B C Black Holes soft X-ray spectrum hard During this phase, the behavior of the jet, revealed by infrared and radio observations, also begins to change. The infrared emission drops almost as soon as the state transition begins (14), indicating a change in the jet properties(density andmagneticfield) close to the black hole. The radio emission begins to vary more dramatically, showing oscilla- tions and flare events superposed on an overall decline (8, 15). At a cer- tain point, there are one or more large radio flares, which can be two or more orders of magnitude more luminous than the previous existing, steadier jet in the hard state. In several notable cases, high-resolution radio observa- tions after such flares have directly resolved radio- or even x-ray–emitting blobs moving away from the central black hole (16, 17), which can be kinematically traced back to the time of the state transition. It has been re- cently shown that in some cases, the ejection is coincident in time with the appearance of the strong QPOs (15). The soft state (D → E). As the spectral transition continues, these strong QPOs disappear, and the over- all level of x-ray variability drops as X-ray spectrum X-ray luminosity SOFT HARD A B C D E F Black Holes
36. “HR-diagram” for BHs: stellar BHs change states in Δt ~ days; AGNs in Δt ≳105 years? phase, the behavior of by infrared and radio so begins to change. mission drops almost tate transition begins a change in the jet ty andmagneticfield) ck hole. mission begins to vary lly, showing oscilla- vents superposed on ne (8, 15). At a cer- are one or more large h can be two or more tude more luminous s existing, steadier jet e. In several notable lution radio observa- flares have directly r even x-ray–emitting way from the central 17), which can be ced back to the time hard transition ing a range of can occur (eve generally occu few percent o nosity (24). In never been co in any BHXR low 1% Eddin source reache state again, w same spectral istics as the in has reappeare disc wind is g state, the sou typically belo of all-sky or re and are obser until their next phases are not ever, for it is that—without X-ray spectrum X-ray luminosity SOFT HARD A B C D E F oles Fender & Belloni 12 Science X-ray luminosity During this phase, the behavior of the jet, revealed by infrared and radio observations, also begins to change. hard transition, although also ing a range of luminosities at w can occur (even in the same s X-ray spectrum SOFT HARD B C Black Holes soft X-ray spectrum hard During this phase, the behavior of the jet, revealed by infrared and radio observations, also begins to change. The infrared emission drops almost as soon as the state transition begins (14), indicating a change in the jet properties(density andmagneticfield) close to the black hole. The radio emission begins to vary more dramatically, showing oscilla- tions and flare events superposed on an overall decline (8, 15). At a cer- tain point, there are one or more large radio flares, which can be two or more orders of magnitude more luminous than the previous existing, steadier jet in the hard state. In several notable cases, high-resolution radio observa- tions after such flares have directly resolved radio- or even x-ray–emitting blobs moving away from the central black hole (16, 17), which can be kinematically traced back to the time of the state transition. It has been re- cently shown that in some cases, the ejection is coincident in time with the appearance of the strong QPOs (15). The soft state (D → E). As the spectral transition continues, these strong QPOs disappear, and the over- all level of x-ray variability drops as X-ray spectrum X-ray luminosity SOFT HARD A B C D E F Black Holes low/hard XRB low-luminosity AGNs, Sgr A* N+06; N+14
37. 1. Usually not in vacuum: accretion flows 2. Deep potential wells → Relativistic effects, spacetime whirlwind → Powerful outflows/jets 3. Impact galaxy evolution 4. Complicated “HR-diagrams”: state transitions Black holes are very rich for astrophysics During this phase, the behavior of the jet, revealed by infrared and radio observations, also begins to change. The infrared emission drops almost as soon as the state transition begins (14), indicating a change in the jet properties(density andmagneticfield) close to the black hole. The radio emission begins to vary more dramatically, showing oscilla- tions and flare events superposed on an overall decline (8, 15). At a cer- tain point, there are one or more large radio flares, which can be two or more orders of magnitude more luminous than the previous existing, steadier jet in the hard state. In several notable cases, high-resolution radio observa- tions after such flares have directly resolved radio- or even x-ray–emitting blobs moving away from the central black hole (16, 17), which can be kinematically traced back to the time hard transitio ing a range of can occur (eve generally occu few percent o nosity (24). In never been c in any BHXR low 1% Eddi source reache state again, w same spectral istics as the in has reappeare disc wind is g state, the sou typically belo of all-sky or re and are obser until their nex phases are not ever, for it is that—withou X-ray spectrum X-ray luminosity SOFT HARD A B C D E F Black Holes galaxy
38. Black Holes, Big Questions ρ, B, v, T of accretion/jets near BHs? What regulates BH HR-diagram and state transitions? Nature of outflows and how they impact galaxies? BH spin astrophysically relevant? ⊵ ⊵
39. Gustavo Soares PhD Artur Vemado undergrad (IC) Henrique Gubolin Msc Fabio Cafardo PhD Raniere Menezes Msc Ivan Almeida undergrad (IC) http://rodrigonemmen.com/group/ Rodrigo Nemmen Open positions for postdocs: Join our team!
40. 1. Population studies of AGNs 2. Time-domain astronomy in gamma-rays 3. Numerical simulations of BH accretion Research strategies
41. Population studies of supermassive black holes (AGNs)
42. log jet power (erg/s) BH astrophysics is scale-free: same behaviour for stellar and supermassive BHs Pre-Swift Swift BAT Fermi GBM/LAT BL Lacs FSRQs log Lγ-rays (erg/s) Nemmen et al. 2012, Science cf. also Merloni+03; Falcke +04; McHardy+06 ~10 MSun 10 8 -10 9 M Sun
43. E out E in Credit: Perley & Cotton (NRAO/AUI/NSF) ˙ Mc2 BH energy efficiency Measurements of efficiency of BH engine Pjet Pjet ˙ Mc2 = = Radio galaxy
44. Using latest constraints on density profiles ˙ M(R) / R0.5 BH energy efficiency (%) ⇢(R) / R 1 Nemmen & Tchekhovskoy 2015, MNRAS ⌘jet ⌘ Pjet/( ˙ M•c2) BH energy output efficiency from X-rays (nearby AGNs)
45. Using latest constraints on density profiles ˙ M(R) / R0.5 BH energy efficiency (%) ⇢(R) / R 1 Nemmen & Tchekhovskoy 2015, MNRAS ⌘jet ⌘ Pjet/( ˙ M•c2) median BH energy output efficiency from X-rays (nearby AGNs)
46. Using latest constraints on density profiles ˙ M(R) / R0.5 BH energy efficiency (%) ⇢(R) / R 1 Nemmen & Tchekhovskoy 2015, MNRAS ⌘jet ⌘ Pjet/( ˙ M•c2) median BH energy output efficiency from X-rays (nearby AGNs) Getting more energy out from black holes than is flowing in
47. Using latest constraints on density profiles ˙ M(R) / R0.5 BH energy efficiency (%) ⇢(R) / R 1 Nemmen & Tchekhovskoy 2015, MNRAS ⌘jet ⌘ Pjet/( ˙ M•c2) median BH energy output efficiency from X-rays (nearby AGNs) Getting more energy out from black holes than is flowing in How? Extraction of BH spin energy
48. Kerr black holes surrounded by thin accretion disks: η up to 40%
49. Kerr black holes surrounded by thin accretion disks: η up to 40%
50. Kerr black holes surrounded by thin accretion disks: η up to 40%
51. Nemmen & Tchekhovskoy 2015, MNRAS; Tchekhovskoy & Nemmen, in prep. Kerr black holes surrounded by magnetically arrested disks (MADs): η up to 300%
52. Nemmen & Tchekhovskoy 2015, MNRAS; Tchekhovskoy & Nemmen, in prep. Kerr black holes surrounded by magnetically arrested disks (MADs): η up to 300%
53. Nemmen & Tchekhovskoy 2015, MNRAS; Tchekhovskoy & Nemmen, in prep. Kerr black holes surrounded by magnetically arrested disks (MADs): η up to 300%
54. Time-domain astronomy in gamma-rays
55. Fermi Gamma Ray Telescope: LSST for high-energy sky, 20 MeV - 300 GeV, whole sky every 3 hours ace based gamma-ray astronomy Diffuse galactic gamma-ray emission Fermi 7-year all sky, >600 MeV Bühler+15
56. Fermi Gamma Ray Telescope: LSST for high-energy sky, 20 MeV - 300 GeV, whole sky every 3 hours ace based gamma-ray astronomy Diffuse galactic gamma-ray emission Fermi 7-year all sky, >600 MeV Bühler+15
57. Monitoring γ-rays for many nearby AGNs: rich variability of central engine; BH heartbeats? Menezes+, in prep.; Nemmen+, in prep. MSc, Raniere Menezes
58. Monitoring γ-rays for many nearby AGNs: rich variability of central engine; BH heartbeats? Menezes+, in prep.; Nemmen+, in prep. PhD, Fabio cafardo poster 121 MSc, Raniere Menezes Results not available yet for public release
59. Numerical simulations of black hole accretion: BH weather
60. What is “black hole weather”? Atmosphere: charged plasma magnetic fields (magnetosphere) Gravity: general relativity (Kerr metric)
61. What is “black hole weather”? Atmosphere: charged plasma magnetic fields (magnetosphere) Gravity: general relativity (Kerr metric)
62. What is “black hole weather”? Atmosphere: charged plasma magnetic fields (magnetosphere) Gravity: general relativity (Kerr metric)
63. BLACK HOLE WEATHER Big BH questions
64. oh wait, Can’t create black holes in lab BLACK HOLE WEATHER Big BH questions sigh…
65. oh wait, Can’t create black holes in lab Virtual lab of relativistic astrophysics BLACK HOLE WEATHER Big BH questions sigh…
66. Gammie+03; Mizuno+06; McKinney+14; Sadowski+14 BH weather has complex physics: Analytical models cannot handle Need numerical simulations, computationally intensive Magnetic fields (MRI – “viscosity”) ➾ MHD Multi-dimensional 3D General relativity (BH) ➾ 3D GRMHD Radiation ➾ 3D GRRMHD cture ture C C
67. Global simulations of weather around spinning BHs: “hurricanes” (jets) a/M = 0.94 Spinning BH •2D •no radiation
68. Global simulations of weather around spinning BHs: “hurricanes” (jets) Units of GM/c2
69. Global simulations of weather around spinning BHs: “hurricanes” (jets) phd, Gustavo soares poster 120 Units of GM/c2
70. Global simulations of weather around spinning BHs: “hurricanes” (jets) phd, Gustavo soares poster 120 MSc, Henrique gubolin poster 79 Pseudo- Newtonian MHD simulations Units of GM/c2
71. Chan+15a,b ApJ radio 10 GHz 1.3mm IR 2.1μm X-rays Soon: Radiative transfer and GPU- accelerated ray tracing in BH spacetimes
72. Chan+15a,b ApJ radio 10 GHz 1.3mm IR 2.1μm X-rays Soon: Radiative transfer and GPU- accelerated ray tracing in BH spacetimes
73. What will the first photograph of a black hole look like? Primary targets: Center of Our Galaxy, M = 4×106 Msun Radiogalaxy M87, M = 6×109 Msun resolution better than 60 μa.s. (orange on the Moon)
74. Summary: Black holes Deep gravity wells = relativity, spin, accretion, jets, outflows ➾ severe black hole weather Important for galaxy formation/evolution soon: first image of an event horizon Numerical simulations: GR+gas+B +radiation BH weather is complicated: need numerical simulations, computationally intensive ⊵ Multiwavelength pop. studies, time-domain, BH “HR-diagram”
75. Github Twitter Web E-mail Bitbucket Facebook Blog Delicious rodrigo.nemmen@iag.usp.br http://rodrigonemmen.com @nemmen rsnemmen http://facebook.com/rodrigonemmen nemmen http://astropython.blogspot.com http://delicious.com/rsnemmen