Reverberation Mapping

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Methods of Measuring Black Hole Masses:

Reverberation Mapping

Misty C. Bentz

Georgia State UniversityMonday, September 12, 2011


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Dynamical methods generally not feasible in AGNs AGNs rare = distant, poor spatial resolution AGNs are bright, outshine the test particles

Use variability instead!Reverberation mapping

relies on time resolution instead of spatial resolution

R size of emission region

V velocity of gas in that region

f order unity scale factor

Black Hole Masses in AGNs

RM Assumptions:1. R (continuum emission region)


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AGN Unified Model

Broad-lineAGNs (Type 1)

Monday, September 12, 2011


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AGN Unified Model

Narrow-lineAGNs (Type 2)




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AGN Unified ModelBlazars





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AGN Unified ModelBlazars





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Inner Solar System

Orbit of Sedna

aphelion = 928AU

= 5.4 light days

AGN Scales or Why Its Hard to Study the BLR in Detail

Radius of Seyfert BLR

~5 light days



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Inner Solar System

Orbit of Sedna

aphelion = 928AU

= 5.4 light days

Embedded in the center of a galaxy

~40Mpc away (z~0.01)

AGN Scales or Why Its Hard to Study the BLR in Detail



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Telescope AGN

Red = continuum

Purple = broad line

Measuring the BLR Radius -- RM Cartoon

BH

Broad Line Region



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Example Data NGC 4151

Cross-correlation"time delay of

broad line response to continuumvariations

Bentz et al. 2006, ApJ, 651, 775



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Time delay (c!) "average BLR radius R

measured for ~50 AGNs

width of variable line emission "line-of-sight BLR gas velocity (V)

fincludes BLR physical details(e.g., inclination, geometry, kinematics)



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Woo et al. 2010

The Fudge Factor f

population average: = 5.2 +/- 1.1

Assume MBH- # relationship

is same for AGNs andquiescent galaxies

#difficult to measure forhigh-L AGNs (z > 0.1)

Morphological biases in #measurements?



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Virial Behavior in the BLR

Peterson & Wandel 2002

V!"-1/2

where measurementsexist for multipleemission lines

Bentz et al. 2010Kollatschny 2003

Mrk110



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Consistency with Dynamical Masses

Stellar and gas dynamical

measurements for 2 AGNswith RM masses

Dynamical and RMmasses aregenerally consistent for

NGC 4151 andNGC 3227

More direct comparisons areneeded, limited by AGN

distances

Davies et al. 2006, Onken et al. 2007,Hicks & Malkan 2008



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Simple RM:

log MBH= 6.82 +/- 0.07

(Bentz et al. 2009)

vs.

Bayesian modeling:

log MBH= 6.51 +/- 0.28

(Brewer et al. 2011)

Brewer et al. 2011

Bayesian Modeling of RM Data

Fits RM datasets withplausible BLR models

i=90defined as

face-on

Models are still simplistic

Need to study more objects



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Echo Mapping - BLR Transfer Function

Bentz et al. 2010

recovered transfer function rulesout outflow

possible evidence for inflow

rotation inflow outflow



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M-L relationship

AGN Lbulgefrom 2-Ddecomposition of optical

HST images

AGN M-L relationship

and

M-L relationship foronly early type

quiescent galaxies

are consistent

Needs to be studied in NIR tominimize dust

AGNs

Bentz et al. 2011, in prep



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Single Epoch MBHEstimates

R Lrelationship yields black

hole mass with onespectrumand twomeasurements: 1. emission line width (V) 2. AGN L!proxy for R



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V



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Si l E h M E i


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L

RV

ALLmass estimates for AGNsusing emission lines are based

on the local observed

R L relationship for H$Monday, September 12, 2011


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NGC 4051

z = 0.00234

PG 0953+414

z = 0.234

Large slit (i.e. 4x10) used to minimize aperture effects!strong starlight contamination at low z

5 x 5 images

AGN Luminosities Host Galaxy Starlight

Mrk 79

z =0.0222



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Updates to RM Database

LAMP 2008

Bentz et al. 2009

MDM 2007

Denney et al. 2010

1 new object

3 replacements2 additions

H$Results Summary:

7 new objects

1 addition

H$Results Summary:

HST Cycle 17 WFC3

Imaging CampaignMonday, September 12, 2011


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CIV R L R l ti hi


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Kaspi et al. 2007

CIV R-L Relationship

Only 7 AGNs,and 5 have similar

luminosities

Slope of CIV R-Lis consistent

with slope of H$R-L

Not enough MgIImeasurements forR-L relationship


S


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Summary

%Reverberation mapping substitutes time resolution for spatialresolution and probes the gravity of the BH

%RM masses consistent with dynamics and with Bayesian modeling

%We are just beginning to acquire data that could soon allow directconstraints on the detailed physics of the BLR gas

%The R-L relationship provides a convenient method for estimating MBHin any broad-lined AGN



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Reverberation Mapping

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