Collaborators: Alex Beelen, Misty Bentz, Frank Bertoldi, Chris Carilli, Pierre Cox, Xiaohui Fan, Shai Kaspi, Dan Maoz, Hagai Netzer, Chris Onken, Pat Osmer, Chien Peng, Brad Peterson, Rick Pogge, Gordon Richards, Francesco Shankar, Adam Steed, Fabian Walter, David Weinberg Marianne Vestergaard University of Arizona First Steps Toward Constraining Supermassive Black-Hole Growth: Mass Estimates of Black Holes in Distant Quasars Drexel University, February 10, 2006 Drexel University, February 10, 2006
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Collaborators: Alex Beelen, Misty Bentz, Frank Bertoldi, Chris Carilli, Pierre Cox, Xiaohui Fan, Shai Kaspi, Dan Maoz, Hagai Netzer, Chris Onken, Pat Osmer,
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Collaborators: Alex Beelen, Misty Bentz, Frank Bertoldi, Chris Carilli, Pierre Cox, Xiaohui Fan, Shai Kaspi, Dan Maoz, Hagai Netzer, Chris Onken, Pat Osmer, Chien Peng, Brad Peterson, Rick Pogge, Gordon Richards, Francesco Shankar, Adam Steed, Fabian Walter, David
Weinberg
Marianne Vestergaard
University of Arizona
First Steps Toward Constraining Supermassive Black-Hole Growth:Mass Estimates of Black Holes in
Distant Quasars
Drexel University, February 10, 2006Drexel University, February 10, 2006
Active Galactic Nuclei• Bright galaxies with a point-
source of non-stellar activity in nuclei
• They are rare – comprise only a few percent of bright galaxies
• The most powerful are called quasars.
• Quasar nuclei outshine their host galaxy light
~10 17 cm -- scale of oursolar system
(Francis et al. 1991)
(Elvis et al. 1994)
Supermassive Black Holes
• How are their mass measured?
• How do they grow?
• How are black holes and galaxies connected?
Black Holes and Galaxy Formation
• Black holes are likely ubiquitous in galaxy centers• MBH – σ* relationship
The M – σ Relationship
(Tremaine et al. 2002; See alsoFerrarese & Merritt 2000; Gebhardt et al. 2000)
Black HoleMass
Bulge Velocity Dispersion
M σ4
• Black holes are likely ubiquitous in galaxy centers• MBH – σ* relationship
– Formation and evolution of bulges and black holes must be intimately connected
– When was it established? And how? – What came first, black hole or bulge (galaxy)?
• Black hole/star-formation feedback (theory)– Negative feedback kills star formation and black hole
growth by expelling gas (e.g., Springel, Di Matteo, & Hernquist 2005)
Black Holes and Galaxy Formation
(Springel et al. 2005)
Black holeactivity
Star formationactivity
Time (Gyr)
• Black holes are likely ubiquitous in galaxy centers• MBH – σ* relationship
– Formation and evolution of bulges and black holes must be intimately connected
– When was it established? And how? – What came first, black hole or bulge (galaxy)?
• Black hole/star-formation feedback (theory)– Negative feedback kills star formation and black hole
growth by expelling gas (e.g., Springel, Di Matteo, & Hernquist 2005)
– Positive feedback stimulate star formation (Silk 2005)
• Consequence: Galaxy bulges form later than supermassive black holes
Black Holes and Galaxy Formation
I. Black Hole Mass a. Determinationsb. Distributions
II. Black Hole – Galaxy Connection
III. Black Hole Evolution
Talk Outline
Talk OutlineI. Black Hole Mass
a. Determinationsb. Distributions
II. Black Hole – Galaxy Connection
III. Black Hole Evolution
mv2 – GmMBH /R = 0
Black Hole Mass
Mm
MBH = v2 R /G
Black Hole Mass
M
MBH = v2 R /G
Black Hole Mass
MBH = v2 R /GBlack Hole Mass
Insert figure from HST/ MW?
R
V
Why Study Quasar Black-Holes?
• Quiescent black holes (in normal galaxies) can only be studied in the nearby Universe
• Quasars are luminous and therefore ideal tracers of black holes to the highest observable redshifts
• Their host galaxies are prime targets for studying galaxy evolution in the early Universe
HST/STIS
8m telescope
30m telesc.
10010
Distance (Mpc)
(Ferrarese 2003)
109
108
Black Hole Mass
How Can MBH be Determined for Active Black Holes?
• Stellar kinematics
• Gas kinematics
• Reverberation mapping
(√)
(√)
√ √
Local Universe Higher-z
Possible Virial Estimators
Source Distance from central source
X-Ray Fe K 3-10 RS
Broad-Line Region 600 RS Megamasers 4 104 RS Gas Dynamics 8 105 RS Stellar Dynamics 106 RS
In units of the Schwarzschild radius RS = 2GM/c2 = 3 × 1013 M8 cm .
Mass estimates from thevirial theorem:
M = f (r V 2 /G)
wherer = scale length of regionV = velocity dispersionf = a factor of order unity, depends on details of geometry and kinematics
Note: the reverberation technique is independent of angular resolution
MBH = f v2 RBLR/G
Reverberation Mapping: RBLR= c τ
Virial Mass Estimates
t1 – t2 =
t = t1
t = t2
t = t3
t = t3 +
Reverberation Mapping Results
NGC 5548, the most closely monitored active galaxy
Continuum
Emission line
Light Curves
(Peterson et al. 2002)
MBH = f v2 RBLR/G
Reverberation Mapping:
–RBLR= c τ
• vBLR
Line width in variable (rms) spectrum
Virial Mass Estimates
t1– t2=
t = t1
t = t2
t = t3
t = t3 +
Reverberation Mapping
NGC 5548, the most closely monitored active galaxy
(Peterson et al. 1999)
• Velocity dispersion is measured from the line in the rms spectrum.– The rms spectrum
isolates the variable part of the lines.
– Constant components (like narrow lines) vanish in rms spectrum
Velocity Dispersion of the Broad Line Region and the Virial Mass
MBH = f v2 RBLR/G
f depends on structure and geometry of broad line region
(based on Korista et al. 1995)
MBH-: Comparison of Active and Quiescent Galaxies
• Reverberation masses appear to fall along the MBH - relation for quiescent galaxies