the physics of galaxy formation institute for computational cosmology university of durham michael...
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![Page 1: The Physics of Galaxy Formation Institute for Computational Cosmology University of Durham Michael Balogh](https://reader038.vdocuments.site/reader038/viewer/2022110102/56649f1b5503460f94c31301/html5/thumbnails/1.jpg)
The Physics of Galaxy The Physics of Galaxy FormationFormation
Institute for Computational CosmologyUniversity of Durham
Michael Balogh
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M31 “Andromeda” galaxy
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Hubble Deep Field/HST
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In the beginning …In the beginning …
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WMAP(Bennett et al. 2003)
In the beginning…In the beginning…
z ~ 1000
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Perturbation GrowthPerturbation Growth
Growth oflinear perturbationsa function of M and
WMAP
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In the beginning …In the beginning …
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Spergel et al. 2003
Mean and 68% confidence errors
Amplitude of fluctuations A=0.83 0.08Spectral index at k=0.05 Mpc-1 ns=0.93 0.03Derivative of spectral index dns/dlnk=-0.031
0.017Hubble constant h=0.71 0.03Total density/critical density tot=1.02 0.04Matter density/critical density m=0.27 0.04Baryon density/critical density b=0.044 0.004Age of the Universe to=13.7 0.2 GyrReionization Redshift zr=17 4Matter power spectrum normalization
8=0.84 0.04
Decoupling redshift zdec=1089 1Age of the universe at decoupling tdec=379 7 kyrThickness of surface of last scatter zdec=195 2Redshift of matter-radiation equality zeq=3233 200
Fit to the WMAP, CBI, ACBAR, 2dFGRS, SN1a and Lyman forest data
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Spergel et al. 2003
Mean and 68% confidence errors
Amplitude of fluctuations A=0.83 0.08Spectral index at k=0.05 Mpc-1 ns=0.93 0.03Derivative of spectral index dns/dlnk=-0.031
0.017Hubble constant h=0.71 0.03Total density/critical density tot=1.02 0.04Matter density/critical density m=0.27 0.04Baryon density/critical density b=0.044 0.004Age of the Universe to=13.7 0.2 GyrReionization Redshift zr=17 4Matter power spectrum normalization
8=0.84 0.04
Decoupling redshift zdec=1089 1Age of the universe at decoupling tdec=379 7 kyrThickness of surface of last scatter zdec=195 2Redshift of matter-radiation equality zeq=3233 200
Fit to the WMAP, CBI, ACBAR, 2dFGRS, SN1a and Lyman forest data
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Spergel et al. 2003
Mean and 68% confidence errors
Amplitude of fluctuations A=0.83 0.08Spectral index at k=0.05 Mpc-1 ns=0.93 0.03Derivative of spectral index dns/dlnk=-0.031
0.017Hubble constant h=0.71 0.03Total density/critical density tot=1.02 0.04Matter density/critical density m=0.27 0.04Baryon density/critical density b=0.044 0.004Age of the Universe to=13.7 0.2 GyrReionization Redshift zr=17 4Matter power spectrum normalization
8=0.84 0.04
Decoupling redshift zdec=1089 1Age of the universe at decoupling tdec=379 7 kyrThickness of surface of last scatter zdec=195 2Redshift of matter-radiation equality zeq=3233 200
Fit to the WMAP, CBI, ACBAR, 2dFGRS, SN1a and Lyman forest data
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Spergel et al. 2003
Mean and 68% confidence errors
Amplitude of fluctuations A=0.83 0.08Spectral index at k=0.05 Mpc-1 ns=0.93 0.03Derivative of spectral index dns/dlnk=-0.031
0.017Hubble constant h=0.71 0.03Total density/critical density tot=1.02 0.04Matter density/critical density m=0.27 0.04Baryon density/critical density b=0.044 0.004Age of the Universe to=13.7 0.2 GyrReionization Redshift zr=17 4Matter power spectrum normalization
8=0.84 0.04
Decoupling redshift zdec=1089 1Age of the universe at decoupling tdec=379 7 kyrThickness of surface of last scatter zdec=195 2Redshift of matter-radiation equality zeq=3233 200
Fit to the WMAP, CBI, ACBAR, 2dFGRS, SN1a and Lyman forest data
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stars= 0.0014 ± 0.00013
>95% of baryons are dark
The matter budget: The matter budget: starsstars
Cole et. al 2002
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The baryon budget: starsThe baryon budget: stars
Coma: XMM-Newton ObservatoryComa cluster
The baryon budget: hot gasThe baryon budget: hot gas
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Remaining dark matter (~84%)
Stars in galaxies (~1%)
Hot gas between galaxies (~15%)
The matter budget: The matter budget: clustersclusters
M ≈ 0.23
b ≈ 0.04
* ≈ 0.003
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The baryon budgetThe baryon budget
Too cool to emit observable
X-ray radiation.
We know it exists, but can’t
directly measure how much
there is
?
?
Stars in Galaxies (~5%) Gas in Galaxies (~2%)
Gas in Clusters (~7%)
Gas in Groups
InterclusterGas
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Ignore the lights…Ignore the lights…
• Most of the baryons are invisible• Most of the matter is non-
baryonic, dark, and weakly interacting
• Most of the energy is not matter
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Ignore the lights…Ignore the lights…
• Most of the baryons are invisible• Most of the matter is non-
baryonic, dark, and weakly interacting
• Most of the energy is not matter
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The easy part: Dark The easy part: Dark mattermatter
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University of Durham
Institute for Computational Cosmology
150 Mpc/h
dalla Vechia, Jenkins & Frenk
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University of Durham
Institute for Computational Cosmology
3 Mpc/h
dalla Vechia, Jenkins & Frenk
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The hard part: baryonsThe hard part: baryons
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Baryonic PhysicsBaryonic Physics
Radiativecooling
Radiativecooling
Invisible baryons: ~106 K
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MergersMergers
Barnes (1992)
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MergersMergers
Barnes (1992)
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Baryonic PhysicsBaryonic Physics
Radiativecooling
Radiativecooling
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The cooling catastropheThe cooling catastrophe
Cooling occurs primarily throughbremsstrahlung radiation, so tcool T1/2-
1
The typical density of haloes is higher at early times: (1+z)3
Thus, gas cools very efficiently in small haloes at high redshift.
•White & Frenk (1991)•Balogh et al. (2001)
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Why so few stars?Why so few stars?
Balogh et al. (2001)
Observations imply */b 0.05
f co
ol
0.1
0.6
0.5
0.4
0.3
0.2
Fraction of condensed gas in simulations is much larger, depending on numerical resolution
Pearce et al. (2000)
Lewis et al. (2000)
Katz & White (1993)
kT (keV)1 10
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Galaxy Luminosity Galaxy Luminosity FunctionFunction
Benson et al. 2003
Overcooling leads to the formation of hundreds more small galaxies than are observed.
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Supernova feedback?Supernova feedback?
M82/Subaru Telescope M82/Chandra Observatory
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Baryonic PhysicsBaryonic Physics
Radiativecooling
Radiativecooling
Feedback
Feedback
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DetailsDetails
z > 1: Feedback z < 1: Environment
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z > 1: Feedbackz > 1: Feedback
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Why are groups Why are groups underluminous?underluminous?
If cluster structure were self-similar, then we would expect L T2
Observations disagree, but why?
Preheating by supernovae & AGNs?
10
1
kT
(keV
)
40 41 42 43 44 45 46
log10Lx (ergs s-1)
L
T2
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K0=400 keV cm2
Isothermal modelM=1015 M0
Preheated gas has a minimum entropy thatis preserved in clusters(Kaiser 1991; Balogh et al. 1999)
Definition of S: S = (heat) / T Equation of state: P = K5/3
Relationship to S: S = N ln K3/2 + const.
Convective Stability: dS/dr 0
Useful Observable: Tne-2/3 K
Only radiative cooling can reduce Tne-2/3
Only heat input can raise Tne-2/3
Ko=400 keV cm2
300
200
100
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Balogh, Babul & Patton 1999Babul, Balogh et al. 2002
log10 LX [ergs s-1]
kT [k
eV
]10
1
0.140 42 44 46
Isothermal model
Preheated modelKo=400 keV cm2
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Sunyaev-Zeldovich EffectSunyaev-Zeldovich Effect
Gomez et al. 2003
Decrement: 150 GHz Intermediate: 220 GHz Increment: 275 GHz
35’Abell 3266
(Inverse-Compton scattering of CMB photons off hot electrons in the ICM)
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S-y0 relation
y0-TX relation
Constraints on “entropy”floor:
S-y0 K0=540 keV cm2
y0-TX K0=300 keV cm2
McCarthy et al. 2003
Sunyaev-Zeldovich EffectSunyaev-Zeldovich Effect
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Does supernova feedback Does supernova feedback work?work?
• Local SN rate ~0.002/yr (Hardin et al. 2000; Cappellaro et al. 1999)
• An average supernova event releases ~1044 J
•Assuming 10% is available for heating the gas over 12.7 Gyr, total energy available is 2.5x1050 J
• This corresponds to a temperature increase of 5x104 K
•To achieve an entropy floor K0 T/2/3:
/avg = 0.28 (K0/100 keV cm2)-3/2
Consider the energetics for 1011Msun of gas:
SN energy too low by at least a factor ~50
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What about active What about active galaxies?galaxies?
Perseus Cluster & 3C 84Perseus Cluster / Chandra
10 kpc
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Bubbles in the Intracluster MediumBubbles in the Intracluster Medium
Quilis, Bower & Balogh 2001
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Bubbles in the Intracluster MediumBubbles in the Intracluster Medium
Quilis, Bower & Balogh 2001
Effective at disruptingcooling in the core,over the ~50 Myrlifetime of the bubble
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The AGN solution?The AGN solution?
• There is ~100 times more energy available in AGN than in supernovae
• Proven effective at disrupting cooling flows
• Details of how this energy is coupled to the surrounding gas are still uncertain
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z < 1: Galaxy Ecologyz < 1: Galaxy Ecology
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B) External? Hierarchical build-up of structure inhibits star formation
A) Internal? i.e. gas consumption and “normal” aging
Steidel et al. 1999
SFR ~ (1+z)1.7
(Wilson, Cowie et al. 2002)
Why Does Star Formation Stop?Why Does Star Formation Stop?
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Galaxy clusters: the end of Galaxy clusters: the end of star formation?star formation?
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Additional physics?Additional physics?
Ram-pressure stripping (Gunn & Gott 1972)
Collisions / harassment (Moore et al. 1995)
“Strangulation” (Larson et al. 1980; Balogh et al. 2000)
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Additional physics?Additional physics?
Ram-pressure stripping (Gunn & Gott 1972)
Collisions / harassment (Moore et al. 1995)
“Strangulation” (Larson et al. 1980; Balogh et al. 2000)
Quilis, Moore & Bower 2000
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Additional physics?Additional physics?
Ram-pressure stripping (Gunn & Gott 1972)
Collisions / harassment (Moore et al. 1995)
“Strangulation” (Larson et al. 1980; Balogh et al. 2000)
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Additional physics?Additional physics?
Ram-pressure stripping (Gunn & Gott 1972)
Collisions / harassment (Moore et al. 1995)
“Strangulation” (Larson et al. 1980; Balogh et al. 2000)
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Abell 2390 (z~0.23)Abell 2390 (z~0.23)3.6 arcmin R image from
CNOC survey(Yee et al. 1996)
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HH in Abell 2390 in Abell 23903.6 arcmin
Balogh & Morris 2000
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300
200
100
0-1
00-2
00-3
00
-200 -100 0 100 200Dec
RA
AC114 (z=0.31)AC114 (z=0.31)
(Couch, Balogh et al. 2001)
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Nod & Shuffle: LDSS++ Nod & Shuffle: LDSS++ (AAT)(AAT)
band-limiting filter +microslit = ~800 galaxies per 7’ field
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HH in Rich Clusters at z~0.3 in Rich Clusters at z~0.3
Balogh et al. 2002MNRAS, 335, 110
Couch, Balogh et al. 2001ApJ 549, 820
LDSS++ with nod and shuffle sky subtraction, on AAT
(Field)
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TimescalesTimescales
Use numerical model ofinfall to estimate timescalefor disruption of SFR
Radial gradients in CNOCclusters suggest ~2 Gyr
Suppressed star formation within several Mpc of cluster centre! What environment is responsible?
Balogh, Navarro & Morris 2000Diaferio et al. 2001
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The 2dFGRS and SDSSThe 2dFGRS and SDSS
2dF Galaxy redshift survey:– spectra and redshifts for 220 000 nearby
galaxies– only photographic plate photometry
Sloan digital sky survey:– goal is spectra for 1 million galaxies, with
digital photometry (ugriz)– Early data release contained 50 000 galaxies
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SFR-Density Relation in the SFR-Density Relation in the 2dFGRS2dFGRS
Lewis, Balogh et al. 2002MNRAS 334, 673
Field
Normalised star formationrate measured from Hin17 nearby clusters
Identified a critical densityof ~1 Mpc-2, where environmental effects become important
This corresponds to lowdensity groups in theinfall regions of clusters
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Importance of EnvironmentImportance of Environment
Star formation is inhibited in only moderately overdense (hence common) environments
Likely due to a relatively slow process; not ram pressure stripping
Impact on global evolution is still unknown
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What Next?What Next?
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Tying star formation to Tying star formation to structure growthstructure growth
Groups Clusters
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Local Groups in the Local Groups in the 2dFGRS/SDSS2dFGRS/SDSS
Based on friends-of-friends catalogue (V. Eke)
Mean SFR appears to be suppressed in all galaxy associations at z=0!
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CNOC2 Groups at z~0.45CNOC2 Groups at z~0.45Deep spectroscopy with LDSS-2 on Magellan 1 (~30 groups)
Infrared (Ks) images from INGRID
Combined with CNOC2 multicolour photometry and spectroscopy, we can determine group structure, dynamics, stellar mass, and star formation history.
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LDSS2 on MagellanLDSS2 on Magellan[OII] [OII]
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The CFHLSThe CFHLS
Survey Area Filters DepthTotal (ks)
StrategyTotal nights
Wide Synoptic
1 8x92 7x7
u* 25.5 6
162
g’ 26.5 2.5
r’ 25.7 2 1 early1 3a later
i’ 25.5 4.3
z’ 24.0 7.2
Deep Synoptic
4 1x1 u* 27 118.8
5.25 nights per run,5 runs a year for each field
202
g’ 28.4 118.8
r’ 28 237.6
i’ 27.8 475.2
z’ 26 237.6
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The CFHLSThe CFHLS
• identify clusters and groups to z=1. Expect ~50 clusters at 1<z<1.5 in Wide Synoptic Survey
• Overlap with XMM Large Scale Survey allows analysis of X-ray properties
• Requires spectroscopic and NIR follow-up
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Galaxy formation Galaxy formation theorytheory
• Need self-consistent feedback model which explains:– galaxy luminosity function– cluster/group X-ray properties– cold fraction of baryons
• This likely requires coupling energy output of AGN to surrounding material. Detailed work is only now beginning.
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SummarySummary
• Underlying galaxy formation model is fairly well established
• However, it is dominated by unknown feedback processes. Wealth of data (esp. from Chandra and XMM-Newton) are shedding light on this, now
• Importance of additional physics in dense environments is currently unknown, but will be established with the completion of large surveys at z~1
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Benson et al. 2002
Z=5
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Benson et al. 2002
Z=3
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Benson et al. 2002
Z=2
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Benson et al. 2002
Z=1
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Benson et al. 2002
Z=0.5
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Benson et al. 2002
Z=0