what happens close to a black hole ?

What Happens Close What Happens Close to a Black Hole ?to a Black Hole ?

A. R. Rao, TIFR, Mumbai

‘‘Symposium on High Energy Astrophysics’Symposium on High Energy Astrophysics’HRI, Feb 18, 2012HRI, Feb 18, 2012

We don’t know

PlanPlan

• Black Holes in the Universe

• Accretion theory

• Disks, Jets and outflows

• Across Mass scales

• The difficulties

• The Astrosat project

• Conclusions

Black HolesBlack Holes

Stellar Structure theoryStellar Structure theory Dynamical mass measurements: Dynamical mass measurements:

compact stars heavier than a few solar compact stars heavier than a few solar massesmasses

A massive object at the center of our A massive object at the center of our galaxygalaxy

Active Galactic NucleiActive Galactic Nuclei Ultra-luminous X-ray (ULX) sourcesUltra-luminous X-ray (ULX) sources Gamma-ray burstsGamma-ray bursts

Force equation:Force equation: Radiation pressure and gas pressure.Radiation pressure and gas pressure.

Chandrasekhar limit

“I do not see how a star which has once got into this compressed state is ever going to get out of it ... It would seem that the star will be in an awkward predicament when its supply of subatomic energy fails.” –Sir Arthur Eddington

Stellar mass Black HolesStellar mass Black Holes Compact objects heavier than neutron Compact objects heavier than neutron

stars/ white dwarfsstars/ white dwarfs Mass function f(M) = P KMass function f(M) = P K3 3 / 2 / 2 G G = M sin= M sin³³ ii / (1 + q)² / (1 + q)²

Cyg X-1: P = 5.6 d Cyg X-1: P = 5.6 d M2 > 9 MM2 > 9 M (~30 M (~30 M)) Last 15 years:Last 15 years: several new sources : transientsseveral new sources : transients

Some statisticsSome statistics

300 million estimated

5% of baryonic mass

20 black hole binaries known

10% of X-ray Binaries

17 transient LM-XRB

(3 always bright)

0.17 - 33.5 days

13 radio bright (5 jets)

Lightest known black hole: GRO J1655-40Lightest known black hole: GRO J1655-40

M = (5.8 – 6.8 MM = (5.8 – 6.8 M) (95% confidence limit)) (95% confidence limit)

Most massive: IC 10 X-1: 33Most massive: IC 10 X-1: 33++3 M3 M(> 21 (> 21 MM))

A Black Hole in the centre of our A Black Hole in the centre of our GalaxyGalaxy

2.9 million x mass of the Sun Doelman et al. 08

Active Galactic Nuclei

• Dynamical centers of some galaxies

• Large lumonisity in tiny spaces

• Powerful sources at all wavelengths

- strong continuum

– X-ray emission most generic property

• Seyfert 1 and Seyfert 2 galaxies, NLS1s,

QSOs, LINERs etc

• BLRGs, NLRGs, BL Lac objects, Blazars etc

– Broad Line region: 0.01 - 1pc; Illuminated by the AGN's photoionizing continuum radiation and reprocess it into emission lines

– RBLR =c t

– V estimated by the FWHM of broad emission line

- M = f (r V 2 /G)

Reverberation mappingPeterson (1997)

Mass from optical emission lines in M 87

M =2.4 109 MM

Macchetto et al. (1997)

Mass from maser observations22 GHz microwave emission

NGC 4258 M=4 107 MM Miyoshi et al. (1995)

Black Hole CensusBlack Hole Census

Two dozen dynamical mass Two dozen dynamical mass measurements of Stellar mass black measurements of Stellar mass black holesholes

Five dozen super-massive black Five dozen super-massive black holes (reverberation mapping, holes (reverberation mapping, stellar/gas dynamics, water maser)stellar/gas dynamics, water maser)

Another two dozen stellar mass and Another two dozen stellar mass and a several thousand AGN from a several thousand AGN from correlations and scaling laws.correlations and scaling laws.

PlanPlan

• Black Holes in the Universe

• Accretion theory

• Disks, Jets and outflows

• Across Mass scales

• The difficulties

• The Astrosat project

• Conclusions

Accretion onto Black Accretion onto Black HolesHoles Rs = 2 GM/c² = 3 km M/ Rs = 2 GM/c² = 3 km M/

MM

ISCO = 3 Rs ; 2200 Hz ISCO = 3 Rs ; 2200 Hz (Rs/2)(Rs/2)

= 0.057 – 0.42= 0.057 – 0.42

Accretion (angular mtm Transport) driven by Accretion (angular mtm Transport) driven by MHD turbulence MHD turbulence

Can support B-fields that thread the black hole Can support B-fields that thread the black hole (stretched) horizon(stretched) horizon

Spectral statesSpectral statesRs = 2 GM/c² = 3 km

M/M

ISCO = 3 Rs ; 2200 Hz (Rs/2)

= 0.057 – 0.42

AGN X-ray AGN X-ray spectrum spectrum

Broad Iron Broad Iron fluorescence linesfluorescence lines

Iron line profile inMCG-6-30-15 (Tanaka et al. 1995)Galactic: Miller 2007

Inner radius Inner radius BHBH spin spin

Spin measurement by Blackbody Spectral fitting

Narayan & McClintock

L T4

PlanPlan

• Black Holes in the Universe

• Accretion theory

• Disks, Jets and outflows

• Across Mass scales

• The difficulties

• The Astrosat project

• Conclusions

GRS 1915+105: A Micro-quasar Proper motions: µa = 17.6 ± 0.4, µr = 9.0 ± 0.1 mas d-1

From line of sight HI absorption D = 12.5 ± 1.5 kpc

Apparent velocities on the plane of sky 1.25±0.15 c and 0.65±0.08 c

True speed of ejecta = 0.92 ± 0.08

Jet angle = 70o ± 2o to the of sight

1997 observations show higher proper motions smaller distance and angle

D

car )cos1(

sin,

VLA observationsMirabel & Rodriguez 1994,

Nature, 371, 46

Spectral Spectral States and States and

JetsJets

Fender, Belloni & Gallo (2004)

Definite pattern of jet activity seen as a function of spectral state (Fender et al. 2004)

24Black Holes: The power behind the scene

X-ray Radio correlation in Galactic Black Hole Sources(Brocksopp et al. 99; Corbel et al. 00; Gallo et al. 02; Markoff et al. 02)

Gallo et al. 2003

PlanPlan

• Black Holes in the Universe

• Accretion theory

• Disks, Jets and outflows

• Across Mass scales

• The difficulties

• The Astrosat project

• Conclusions

Quasars/ micro-quasars

Variability, Luminosity & Variability, Luminosity & Mass of Black HolesMass of Black Holes

McHardy et al. 2006, Nature, 444, McHardy et al. 2006, Nature, 444, 730730

TTBB : M : MBHBH22 / L / Lbolbol

Arevalo et al. 2008

QPO in AGNsQPO in AGNs

RE J1034+396: Gierlinski et al. 2008

PlanPlan

• Black Holes in the Universe

• Accretion theory

• Disks, Jets and outflows

• Across Mass scales

• The difficulties

• The Astrosat project

• Conclusions

• Mass measurements available for 39 AGNs and 17 XRBs.

• Typical accuracy

~ 30% for AGNs

~ 10% for XRBs

30

Black hole mass measurements

Radio

Lx/ LEdd

Timing

Spectrum

Accretion onto Black holesAccretion onto Black holes

Theorists, claiming thatTheorists, claiming that there is remarkable success inthere is remarkable success in the study of black hole the study of black hole accretion disks, lament that the accretion disks, lament that the most pressing problem of the day most pressing problem of the day is to match is to match ``our theretical knowledge ``our theretical knowledge to actual observed phenomena'' to actual observed phenomena'' (Abramowicz \& Fragile, arxiv1104.5400)(Abramowicz \& Fragile, arxiv1104.5400)

Observers can define a ``small number of states and their association with jets providing a good frame work to base theoretical studies'‘ (Belloni et al, 2011, arxiv1109.3388

``We are still a long way``We are still a long wayFrom a theory of accretion From a theory of accretion Discs with real predictive Discs with real predictive

Power’’ – King, arXiv1201.2060Power’’ – King, arXiv1201.2060

Cyg X-1 hard: disk (scattered) Compt. Reflection

Cyg X-1 soft: non-thermal Compt

XTE J1550-564: VHS/IS

GRS 1915+105

RXTE-PCAHEXTEOSSE

dN/dE = E- Photons/cm2/s/keV E*E- keV/cm2/s/keV (cm2/s) E² * E- keV(keV/cm2/s/keV)

Abs*(diskbb+cpompST)

Wide band spectrum of a black hole candidate

EQPair: Zdziarski et al.

Eqpair for multiple sources

GRS 1915+105

Cyg X-3

Crab

PlanPlan

• Black Holes in the Universe

• Accretion theory

• Disks, Jets and outflows

• Across Mass scales

• The difficulties

• The Astrosat project

• Conclusions

ASTROSAT

LAXPC

UVIT

SSM

CZT

SXT

Astrosat Instruments  1. LAXPC : Large Area X-ray Proportional Counters; Aeff ≈ 6000 cm2; FOV =10 X 10; 3-80 keV; E/ΔE ≈ 5 to 12.

2. CZT Imager: Cadmium-Zinc-Telluride array with Coded Aperture Mask; Aeff = 500 cm2; FOV = 60 X 60;10 – 100 keV; E/ΔE ≈ 20 to 30. 3. SXT : Soft X-ray Telescope using conical-foil mirrors A eff ≈ 200 cm2 ; FOV = 0.50; (~3‘ res); 0.3-8 keV; E/ΔE ≈ 20 to 50.

4. SSM : Scanning Sky Monitor (SSM) with 3 PSPCs and coded aperture mask; A eff ≈ 30 cm2 (each); 2-20 keV.

5. UVIT : Ultraviolet Imaging Telescope (UVIT) two telescopes each with 38 cm aperture; near-uv , far-uv and visible bands.

Astrosat Science Objectives…Astrosat Science Objectives…

• Multi-wavelength studies (UV to X-rays) spectra, variability.• Periodic and aperiodic variability.• Broad band X-ray spectroscopyBroad band X-ray spectroscopy non-thermal components, non-thermal components, cyclotron lines.cyclotron lines.• Surveys All-sky, Galactic plane, deep.

Suzaku Vs CZT-Imager

Mrk 110Mrk 110

Binary X-ray Pulsars with AstrosatSimulated 10 ks observations of a hard X-ray pulsar spectrum. The cyclotron lines are nicely resolved by ASTROSAT .

ConclusionsConclusions

• The inner-most regions of the accretion disk in Black Hole sources are emitters of non-thermal radiation.

• Precise hard X-ray continuum spectroscopy is needed to understand this region.

• Implications for a variety of phenomena in high energy astrophysics: GRBs, accretion physics, AGN growth….

• Astrosat would be a small but decisive step forward.