t. j. cox
DESCRIPTION
Feedback by Merger-driven AGN. T. J. Cox. Lars Hernquist, Phil Hopkins. - PowerPoint PPT PresentationTRANSCRIPT
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T. J. Cox
Gurtina Besla (CfA), Tiziana Di Matteo (CMU), Suvendra Dutta (CfA), Loren Hoffman (CfA), Patrik Jonsson (UCSC), Dusan Keres (CfA), Elisabeth Krause (CfA/Bonn), Adam Lidz (CfA), Desika Narayanan (Arizona), Joel Primack (UCSC),Brant Robertson (KICP), Rachel Somerville (MPIA), Volker Springel (MPA), Josh Younger (CfA)
Lars Hernquist,Phil Hopkins
Feedback Feedback by Merger-by Merger-driven AGNdriven AGN
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projected gas distribution
projected stellar distribution
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• Tidal torques large, rapid gas inflows (e.g., Barnes & Hernquist 1991)
• Triggers starburst (e.g., Mihos &
Hernquist 1996)• Feeds BH growth (e.g., Di Matteo et al.
2005)• BH Feedback disperses gas and
reveals optical QSO• Merging stellar disks grow
spheroid
Requires:– Major (3:1) merger– supply of cold (i.e., rotationally
supported) gas
Generic Outcome of Gas-Rich Galaxy MergersGeneric Outcome of Gas-Rich Galaxy Mergers
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Cox et al. (2006)
Proposed Chronology of a Galaxy MergerProposed Chronology of a Galaxy Merger
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Note #1: Morphology at Quasar phaseNote #1: Morphology at Quasar phase
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Note #2: Not all AGN activity is triggered by Note #2: Not all AGN activity is triggered by mergersmergers
Low-mass BH (if bulge-less galaxy) or moderate-mass BH accreting by stochastic triggering, minor merger, or …
High-mass BH accreting ambient gas or participating in another gas-rich major merger or …
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Types of Feedback During Types of Feedback During Gas-Rich Galaxy MergersGas-Rich Galaxy Mergers
1. Merger/Gravitational Feedback: collisional heating of gas owing to the interaction itself
2. Star Formation Feedback: energy/mass input from high-mass stars
3. QSO Feedback: energy input from high Eddington rate BH accretion. Note that this is separate from, but a necessary precursor to, “Radio-mode” feedback.
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A Typical Galaxy Merger (take 2)A Typical Galaxy Merger (take 2)
projected gas distribution Mass-weighted gas temperature(on a larger scale)
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• Hot (~Tvir) gas is produced by collision-induced shocks (and therefore depends on the merging orbit)
• Mainly affects low-density (outer-disk, tidal) gas (a small fraction of the original gas content)
• Insufficient heating to unbind gas
Cox et al. (2004/6)
Gravity/Merger FeedbackGravity/Merger Feedback
Contours show the X-ray emission from from hot gas.
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• Basic energetics suggest that Efb,SN ~ Efb,BH
• Timescale for energy injection is NOT equivalent SP < SF
The power can be very different
• Location of energy injection is different: quasar feedback is deposited in the galactic center, star formation feedback is spread throughout the galactic disk
Feedback from Star Formation and Black HolesFeedback from Star Formation and Black Holes
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BH feedback during the “active phase” becomes increasingly dominant for systems of larger (total) mass
Cox et al. (2007)
Relative Feedback During “Active Phase”Relative Feedback During “Active Phase”
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BH feedback during the “active phase” regulates the mass of the black hole, and leads to the MBH- relation.
Di Matteo et al. (2005), Springel et al. (2005)
BH Feedback During “Active Phase”BH Feedback During “Active Phase”
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• Significant coronae of hot gas is produced
• Emits X-rays (consistent with E scaling relations)• Cooling time and entropy are increased
(Small systems may never cool and large systems are “primed and
ready” for radio-mode feedback -see Phil’s talk from Monday)• Ejects metals• AGN contributes (significantly to the entropy), but
SN-driven winds dominate the ejection of mass and metals
The Influence on Gas in the Merger The Influence on Gas in the Merger RemnantRemnant
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Which Feedback Which Feedback Influences the Structure Influences the Structure of Merger Remnants?of Merger Remnants?• Stellar feedback regulates star formation & determined the structure of the merger remnant
• BH feedback does not!w/ BH
w/o BH
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• Star formation quenched by black hole feedback, remnant reddens quickly
• Less power from starburst driven winds (factor ~ 0.1)
Springel et al. (2004), Di Matteo et al. (2005)
with black hole
Color Evolution of Merger RemnantsColor Evolution of Merger Remnants
without black hole
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Color Evolution of Merger RemnantsColor Evolution of Merger RemnantsDo we really NEED BH feedback to produce red remnants?
high gas content
moderate gas content
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• Outflows visible in absorption (Mathur’s talk earlier, Arav/Trump in QSO, Rupke/Martin in ULIRGs, Tremonti in post-
starburst galaxies, Weiner in DEEP2)
• CO spectra (Appleton et al. 2002, Narayanan
et al. 2006, Iono et al. 2007)
• SZ (Evan’s talk, Juna’s suggestion)
Signatures of BH Feedback?Signatures of BH Feedback?
Narayanan et al. (2006)
NGC 6240 (Iono, et al., 2007, see also Appleton, et al. 2002 in NGC 985)
Tremonti et al. (2006)
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Conclusions: 3 Types of Feedback During Conclusions: 3 Types of Feedback During Gas-Rich Galaxy MergersGas-Rich Galaxy Mergers
1. Merger/Gravitational Feedback: collisional heating of gas owing to the interaction itself* additional heating source
2. Star Formation Feedback: energy/mass input from high-mass stars* dominant source of feedback, regulates star formation & remnant properties* very likely determines mass and metal ejection
3. QSO Feedback: energy input from high Eddington rate BH accretion. Note that this is separate from, but a necessary precursor to, “Radio-mode” feedback.* very brief, but powerful* regulates black hole mass* contributes to heating of remaining gas* contributes to metal ejection* contributes to color evolution in massive, high gas fraction mergers
Observational evidence ….. ??