Radio Galaxies in XRay Light: Problems and Processes

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Radio Galaxies in X-Ray Light Problems and
Processes

• Dave De Young
• NOAO

Radio Galaxies in the Chandra Era
8-11 July 2008
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Major Unresolved Issues Radio Galaxies in the
Pre-Chandra era

• Origins of Energetic Particles How and Where
• Formation of Bipolar Outflows
• Collimation Mechanisms
• Outflow Speeds
• Outflow Content
• Total Energies
• Outflow Lifetimes

3
Major Resolved Issues Radio Galaxies in the
Pre-Chandra era

• Morphology/Radio Luminosity Classification
  FR-I and FR-II
• Radio Radiation - Incoherent Synchrotron
• Must Have Relativistic Electrons and Magnetic
  Fields
• Superluminal Features on Small Scales

4
Some Major Revelations from Chandra

• Extended X-Ray Emission From Jets, Hot Spots, and
  Lobes

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Revelations from Chandra Large Scale X-Ray Jets

• Electron Synchrotron Lifetimes in Equipartition
  Fields
• X-Ray Decades to Centuries
• Optical and UV Millennia
• Therefore High Energy Electrons Cannot Have Been
  Energized Only in Nucleus
• Immediate Impact on
• Models

6
Revelations from Chandra Low Power (FR I) X-Ray
Jets

• Electron Synchrotron Models Can Work
• Single SED Can Fit Radio to X-Ray
• Requires Local Acceleration in Knots
• Can Produce Offsets
• Simultaneous Variations at X-ray to Radio
• Problems/Uncertainties
• Distributed Acceleration Two Populations?
• Occasional Wrong SED
• No Radiative Cooling Signatures?

7
Revelations from Chandra Hot Spots and Lobes

• X-Ray Emission Consistent with SSC and IC/CMB
  Under Equipartition Conditions
• First Verification of Equipartition Assumption
• Kataoka Stawartz 2005, Croston et al. 2005

8
Revelations from Chandra Large Scale (QSO, FR
II, Blazar) X-Ray Jets
Schwartz et al. 2000
Sambruna et al. 2004
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Large Scale X-Ray Jets
Harris Krawczynski 2006
Siemiginowska et al. 2007, 2008
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Large Scale X-Ray Jets

• The IC/CMB Model
• Tavecchio et al. 2000, Celotti et al. 2001
• PKS 0637-752 G 10
• Reproduces SED
• Has Three Basic Assumptions
• Equipartition Conditions
• Relativistic Motion on 10-100 Kpc Scales
• Population of Low Energy electrons

Schwartz et al. 2000
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Large Scale X-Ray Jets

• Electron

Kataoka Stawartz 2005
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Large Scale X-Ray Jets The IC/CMB Model

• Some Issues
• Low Energy ? 10-100 Long Electron Lifetimes
• Why X-Ray Knots?
• Required Beaming Angles Imply Jet Lengths 1 Mpc
  or More, gtgt FR II Jets
• Equipartition Low Energy End of Spectrum May
  Imply Too Much Energy
• Bulk Speeds at 100s kpc gtgt Other Derived Values

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IC/CMB Issues
Kataoka et al. 2008
3C 33 Kraft et al. 2007
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Revelations from Chandra Large Scale X-Ray Jets

• Reacceleration for Electron Synchrotron
• First Insights into Energy Injection Question
• Stringent Requirements on Shock Models
• Can Account for Most Low Power FR-I Jets
• Possibility of IC/CMB for FR-II/Quasar Jets
• Requires Relativistic Bulk Motion at 100s kpc
• First Possible Clues to Jet Speeds on Large
  Scales
• Implies Low Energy Electron Population
• First Possible Constraints on ?(min)

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Other Radio Galaxy Results from Chandra

• Radio Galaxy Interactions with the Environment
• E.g., Cen A (Kraft et al. 2007)

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More Major Revelations from Chandra

• Radio Galaxy Inflated Cavities in Clusters

NGC 1285/Perseus Fabian et al. 2000
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Radio Source Cavities

• N1275

Fabian et al. 2000
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Radio Source Cavities in Clusters

• Chandra A2052 6cm VLA (3C 317)

Blanton et al. 2001, Burns 1990
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Properties of Radio Source Cavities and
Shells

• Morphology
• Limb Brightened, Relaxed Structure
• NOT Head-Tail or Normal FR-I
• Small/No Jets, but t 10 yr
• Tens of kpc in Diameter
• Inferred Properties
• In Pressure Equilibrium
• Generally Moving Subsonically
• Shell and Surroundings Cool
• Buoyant Bubbles

7
syn
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Relic Sources in Clusters

• N1275

74 MHz
Fabian et al. 2002
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Properties of Radio Relics

• They Are Intact! At Times gtgt t
• Reside 30-50 kpc From Cluster Center
• Diameter 10-20 kpc
• Buoyant Risetimes 10 yr gt Synchrotron
  Lifetime
• Equilibrium Implies U gtgt U
• PdV Work 10 erg (or More)

instab
8
int
equip
59
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Calorimetry of Radio Galaxy Outflows

• After gt 35 Years of Assumptions and Guessing

McNamara Nulsen 2007
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Calorimetry of Radio Sources in Clusters

• MS 0735
• Z 0.22
• pdV 10 erg!

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McNamara et al. 2005, 2007
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Stability of Relic Sources in Clusters

• t gtgt t

buoy
R-T, K-H
vs
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The Cooling Flow Problem and Heating Due to
Radio Sources

• Sound Waves?
• Shock Waves?

?P/P
Fabian et al. 2005
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What Have We Learned and What Remains Unsolved?

• Origins of Energetic Particles In Situ
  Acceleration Required in Addition to Nuclear
  Processes
• Formation of Bipolar Outflows ? See Finis
• Collimation Mechanisms ? See Finis
• Outflow Speeds May Be Relativistic on Mpc
  Scales
• Outflow Content Coupled to Speed Question?
• Total Energies Enormous Progress Firm Limits
• Outflow Lifetimes See Item 4

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A Possible Path to Further Progress Jet
Interactions With Their Environment

• Key Issue The Coupling of AGN Outflow to the
  Surrounding Medium
• Ambient Medium with Known Properties
• Determination of Dominant Physical Processes at
  Work
• Constrain Basic Parameters of Outflow

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AGN Outflows

• FRII

3C223 20cm
3C98
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AGN Outflows

• FRI

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AGN Outflows

• FRI

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AGN Outflows
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AGN Outflows

• Surface Brightness

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Outflow Interaction with Ambient Medium

• Fully Non-Linear K-H Instability
• Development of Turbulent Mixing Layer

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Mixing Layers

• Thickness Grows with Distance/Time
• Mixing Layer Can Permeate Entire Jet

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Mixing Layers

• Entrainment Very Effective
• Ingest Digest Process

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Mixing Layers

• K-H and Mixing Layers in Supersonic Flows
• Relativistic Flows
• 3D Simulations
• Rigidity
• Deceleration
• Development of
• Shear/Mixing Layers

Aloy et al. Marti et al. 1999-2003
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The Effect of Magnetic Fields

• Can Stabilize In Principle
• Three Dimensional MHD
• For High Beta gt 100
• Evolves to Turbulence
• Turbulent B Amplification
• Enhanced Dissipation due
• to Magnetic Reconnection
• Instability Remains
• Essentially Hydrodynamic

Ryu et al. 2000
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Mixing Layers

• MHD Plus Relativistic

Mizuno et al. 2007
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Outflow Interaction Via Surface Instabilities

• Virtually Universal (One Possible Exception)
• Present at Some Level in Outflows in All
  Environments
• Global
• Involve Most of Jet Surface for Long Times
• Inevitable (?)
• Very Special Circumstances Required to Prevent
  Occurrence

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Consequences of Mixing Layers

• Saturated Mixed Jets - and FR I Source
  Morphology

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Consequences of Mixing Layers

• Entrainment
• Deceleration
• Spine/Sheath Structure
• Decollimation
• How Much of Each?
• TanT (? /? ) / M

a
3C223 20cm
1
2
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Consequences of Mixing Layers IC/CMB Models

• Can G 10 to Mpc be Sustained?
• Other Measures of G v Structure
• Is U gtgt U ?
• Implications for Content
• What is Too Much Energy?

p
B
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Consequences of Mixing Layers IC/CMB Models
Other Issues

• Evidence for Sustained Energy Transport
• Where are Debeamed Jets?
• Probable Need for Jet Models
• With Complex Internal Velocity
• Structure

Hardcastle 2006
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Another Possibility

• Poynting Flux Jets
• Origins Well Defined
• Initial Collimation Solved
• Development of Mixing
• Layer Not Clear
• Long Term Collimation?
• Particle Content?

Li et al. 2006
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Evolution of Turbulent Flows

• Development of the Turbulent Cascade

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Issues for This Week

• The FRI / FRII Dichotomy (and IC/CMB Jets)
• Difference in Degree or Kind?
• Nature vs. Nurture
• Jet Content
• Jet Speed
• Collimation
• Difficult with External Pressure ( d )
• Difficult with Magnetic Fields

a
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Issues for This Week

• Poynting Flux Jets
• Are There Unique Observational Signatures?
• Radio Sources in Clusters
• Cooling Flows, Feedback etc.
• Consequences for General Radio Sources
• Total Energies
• Energy Fluxes
• Outflow Speeds
• Jet Content