Spin Measurements of Black Holes Thomas Dauser

Irradiation of an Accretion Disk by a Jet:
Spin Measurements of Black Holes
Thomas Dauser 1
in collaboration with
J. Wilms 1 , J. Garcia (CfA/UMd), R. Duro 1 ,
C. S. Reynolds (UMd), N. Schartel (ESA-ESAC),
K. Pottschmidt (CRESST/UMBC/NASA-GSFC),
M. A. Nowak (MIT), and many others
1 Dr. Karl Remeis Observatory Bamberg & ECAP

What can we learn from the Spin of a Black Hole
Example: Galaxy Evolution
Steady Growth Galaxy Mergers
P(a)
1
0.8
0.6
0.4
0.2
0
-1
Bardeen (1970) Volonteri et al. (2005) King et al. (2008)
0
spin a
1
P(a)
1
0.8
0.6
0.4
0.2
0
-1
0
spin a
1
1
0.8
0.6
0.4
0.2
0
-1
0
spin a
Spin: −1 < a < 1 (Rotation Velocity with respect to the Accretion Disk)
⇒ Spin could distinguish Galaxy Evolution Models
P(a)
1

What can we learn from the Spin of a Black Hole
Example: Jet Formation
Jet-Formation is connected in most models to the BH spin (e.g.,
Blandford & Znajek, 1977)
Jet Power
Spin
Garofalo et al. (2010):
most powerful jets from
retrograde (a = −1)
BHs
→ Measuring Jet-Power
vs. Spin relation
constrains Jet Models

Irradiation and Reflection
Jet
Accretion Disk

Irradiation and Reflection
Jet
(Reynolds, 1996)
Accretion Disk

Irradiation and Reflection
Jet
Counts per unit energy (arb.)
10 7
10 6
10 5
10000
1000
100
10
1
0.1
0.1
1
Energy [keV]
(Reynolds, 1996)
Ionized Reflection (García & Kallman, 2010; García et al., 2011)
10
Accretion Disk
100

Relativistic effects close to the black hole
β[rg]
40
20
0
-20
-40
-60
-40
-20
α[rg]
0
-0.3 -0.2 -0.1 0.0 0.1 0.2 0.5 1.0
Redshift z
20
40
1.4 1.3 1.2 1.1
E/Ee
1 0.9 0.8 0.6 0.4 -10
0
10
(Dauser et al., 2010)
Rotating Black Hole: Metric depends on M (mass) and a (spin)
→ special relativistic beaming, light bending, and gravitational redshift
(Kerr, 1963; Cunningham, 1975; Fabian et al., 1989; Laor, 1991; Dovčiak et al., 2004; Dauser et al., 2010)
60
10
0
-10
0
10
10
0

Broad Emission Lines
=
Flux [a.u.]
3
2.5
2
1.5
1
0.5
0
+
β[rg]
4.5
40
20
0
-20
-40
-60
-40
-20
α[rg]
0
-0.3 -0.2 -0.1 0.0 0.1 0.2 0.5 1.0
Redshift z
20
40
1.4 1.3 1.2 1.1
E/Ee
1 0.9 0.8 0.6 0.4 -10 0
10
5
Fe Kα (6.4keV)
5.5 6
Energy [keV]
6.5
60
10
0
7
-10
0
10
10
0

Diagnostic potential: inclination
θ = 40 ◦
05◦ θo
10 ◦
20 ◦
30 ◦
40 ◦
50 ◦
60 ◦
70 ◦
80 ◦
5
0.8
ǫ=0.5
a=1.0
E/Ee
0.9
1.0
5.5 6
Energy [keV]
6.5
θ = 80 ◦
1.1
7
10
8
6
4
2
0
Flux [a.u.]

Diagnostic potential: Irradiating Source
h
h=3rg
h=10rg
h=25rg
h=50rg
h=100rg
h=500rg
5
θ=40 ◦
a=+0.99
6
Energy [keV]
determines the incident radiation on the accretion disk
→ low height implies enhanced irradiation of the inner parts
radially extended sources are also possible → Jets
7
12
10
8
6
4
2
0
Flux [a.u.]

Diagnostic potential: black hole spin
a
+1.0
+0.8
+0.6
+0.3
+0.0
−0.3
−0.5
−1.0
5
0.8
θo=40 ◦
ǫ=3.0
E/Ee
0.9
1.0
5.5 6
Energy [keV]
6.5
possible Spin values: a = −1...1
high Spin −→ broad line
1.1
7
4
2
0
Flux [a.u.]

Observations of Broad Iron Lines
AGN MCG−6-30-15: a > 0.98
(Brenneman & Reynolds, 2006; Miniutti et al., 2007)
both instruments measure the same line shape
Ratio
1.1
1.05
1
4
5
6 7
Energy [keV]
stellar mass BH Cyg X-1:
a > 0.9 (Duro & Dauser et al., 2011)
most prominent Kα line in a stellar
mass BH
8

... yes, broad lines are everywhere
Data/Model
0.9 1.0 1.1 1.2 0.9 1.0 1.1 1.2
stellar mass Black Holes
XTE J1550−564 GRO J1655−40
1.0 1.2
0.8
2 4 6 8 10 2 4 6 8 10
Cygnus X−1
1.1
1.0
GRS 1915+105
2 4 6 8 10 2 4 6 8 10
Energy [keV]
after Miller (2007)
0.9 0.95 1 1.05 1.1
data/model
AGN
NGC 3783 (Brenneman et al., 2011)
5
Energy (keV)
NGC 3516 (Iwasawa et al., 2004)

Constraining the Spin from Observations
How good can we distinguish high spin from low spin?
extended Jet compact Jet
high Spin low Spin
2 4 6
2 4 6
Energy [keV] Energy [keV]
1
0.8
0.6
0.4
0.2
0
1
0.8
0.6
0.4
0.2
0
Flux [a.u.]
Flux [a.u.]
(a)
(b)
a = 0.99
a = 0
a = 0.99
a = 0
4
6
Energy [keV]
1.15
1.1
1.05
1
0.95
1.15
1.1
1.05
1
0.95
Ratio
Ratio

Constraining the Spin from Observations
How good can we distinguish high spin from low spin?
extended Jet compact Jet
high Spin low Spin
2 4 6
2 4 6
Energy [keV] Energy [keV]
1
0.8
0.6
0.4
0.2
0
1
0.8
0.6
0.4
0.2
0
(a)
(b)
a = 0.99
a = 0
a = 0.99
a = 0
4
6
Energy [keV]
A detected broad line yields the spin and indicates a compact
emission region compact emission region. (Dauser et al., 2013)
Flux [a.u.]
Flux [a.u.]
1.15
1.1
1.05
1
0.95
1.15
1.1
1.05
1
0.95
Ratio
Ratio

Robust Spin Estimation
AGN 1H0707−495: iron Kα and Lα line detected
νFν[10 −12 × ergs s −1 cm −2 ]
Ratio
1
0.1
0.01
1.5
1
0.5
0.5 1 2
Energy [keV]
5 10
Dauser et al. (2012)
first AGN with
detected iron Kα and
Lα
(see, e.g., Fabian et al., 2009;
Zoghbi et al., 2010)
two reflection
components with
different ionization,
high spin (a > 0.99),
and low jet height
(h < 4rg)

Robust Spin Estimation
stellar mass BH Cyg X-1: Broad Band Spectrum
νFν [10 −6 × ergs s −1 cm −2 ]
χ
10 XMM-Newton RXTE-PCA RXTE-HEXTE
5
2
1
5
3
1
-1
-3
-5
5 10 20 50
Energy [keV]
100
Integral
200
500
Duro & Dauser et al. (2013, in
prep.)
Broad Band
Coverage
(Simultaneous
observations) ( first
robust stellar mass BH spin
measurement)
Cygnus X-1 is a fast
rotating black hole
(a > 0.9), and
compact emission
region (h < 4rg)
Spin in agreement
with the “disk-spin”
method (Gou et al., 2011)

Summary
Relativistic effects distort reflection features produced close to the BH
−→ “Broad Emission Lines”
“Line Shapes” are sensitive to the Spin and other parameters
A detected broad line yields the spin and indicates a compact emission
region compact emission region
Additional information (e.g.,Broad band spectra) is necessary for robust
spin estimates.

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