Presentation - Chandra X

Precipitation-Regulated
Galaxies
G M Voit / Michigan State University
Fundamental Questions
Precipitation-Regulated Galaxies
G M Voit
1
Precipitation & Galaxy Evolution
What turns galaxies on and off?
What quenches
star formation at
Mhalo > 1012 MSun?
QUENCHING
G M Voit
Why is star
formation in
small galaxies
so inefficient?
What limits star
formation in the
most massive
galaxies?
How are
spheroids
linked to
black holes?
Precipitation & Galaxy Evolution
What turns galaxies on and off?
What quenches
star formation at
Mhalo > 1012 MSun?
How does
feedback work?
QUENCHING
G M Voit
Why is star
formation in
small galaxies
so inefficient?
What limits star
formation in the
most massive
galaxies?
How are
spheroids
linked to
black holes?
Precipitation & Galaxy Evolution
Circumgalactic Conditions
Tumlinson+ 11 (COS-Halos)
Most of a galaxy’s
baryons & metals are
in the CGM
G M Voit
Precipitation & Cluster Cores
Precipitation-Regulated Galaxies
G M Voit
2
Precipitation-Regulated Galaxies
G M Voit
NGC 1275 / Fabian / NASA
Precipitation & Galaxy Evolution
Cold Triggering of AGN Feedback
Cavagnolo+ 08
Black-Hole
Power
Requires
Chandra-like
resolution
Multiphase
Gas
G M Voit
Core Entropy Index = K0 = kTne-2/3
Precipitation-Regulated Galaxies
Instability in a Thermally Balanced Medium
McCourt+ 2012, Sharma+ 2012
ENZO: Greg Meece
If the medium is kept in global thermal balance by feedback,
then the threshold for formation of multiphase gas is:
tcool/tff ~ 1 in a box
tcool/tff ~ 10 in a spherical potential
G M Voit
… but see Meece, O’Shea, & Voit 2015
Voit & Donahue 2015; data: Cavagnolo thesis
Dependence of LH⍺ on
min(tc/tff) looks more
like a steep ramp than a
threshold.
1043
1042
LHα in aperture (erg s-1)
Precipitation-Regulated Galaxies
Evidence for Precipitation
1040
Implies a very stiff
black-hole feedback
response that
maintains tc/tff ~ 10 for
most systems.
1039
But there are outliers
extending to tc/tff ~ 50.
1041
1038
G M Voit
1
10
min(tc/tff)
100
Voit & Donahue 2015; data: Cavagnolo thesis
Heat Input
1043
1042
LHα in aperture (erg s-1)
Precipitation-Regulated Galaxies
Evidence for Precipitation
Declining
Precipitation
Dependence of LH⍺ on
min(tc/tff) looks more
like a steep ramp than a
threshold.
1040
Implies a very stiff
black-hole feedback
response that
maintains tc/tff ~ 10 for
most systems.
1039
But there are outliers
extending to tc/tff ~ 50.
1041
Increasing
Precipitation
Cooling
1038
G M Voit
1
10
min(tc/tff)
100
10
11
Precipitation Threshold:
2.0 < max(kTX) < 10.0
1. Use 250 km/s
singular isothermal
sphere for the stars.
1010
2. Use NFW halo with
c500 = 3 for the dark
matter.
K0
tcool (years)
Precipitation-Regulated Galaxies
Cooling-Time
Profiles
Voit+ 2015, Nature
100
109
3. Calculate tff(r).
30
4. Multiply by 10.
108
no cooling
isothermal core
conductive balance
precipitating
baseline
10
G M Voit
107
1
10
r (kpc)
100
Baseline: Voit+ 2005
No Cooling: Voit+ 2002
1000
Conduction: Voit 2011
11
11
10
10
Multiphase Gas
No Multiphase Gas
2-10 keV, Hα
0.5-2 keV, far-IR
2-10 keV, no Hα
10
10
10
10
t cool (years)
Precipitation-Regulated Galaxies
Cooling-Time
Profiles
Voit+ 2015, Nature
K0
K0
100
100
30
30
99
10
10
88
10
10
10
no cooling
isothermal core
conductive balance
precipitation
baseline
77
10
10
0.1
0.1
1.0
1.0
10.0
10.0
r (kpc)
100.0
100.0
0.1
1000.0
10
no cooling
isothermal core
conductive balance
precipitation
baseline
1.0
10.0
r (kpc)
100.0
1000.0
G M Voit
11
11
10
10
Multiphase Gas
No Multiphase Gas
2-10 keV, Hα
0.5-2 keV, far-IR
2-10 keV, no
10
10
10
10
K0
K0
Requires 100
Chandra-like
resolution
100
t cool (years)
Precipitation-Regulated Galaxies
Cooling-Time
Profiles
Voit+ 2015, Nature
99
10
10
Entropy Threshold
30
30
Precipitation Radius
88
10
10
10
G M Voit
no cooling
isothermal core
conductive balance
precipitation
baseline
77
10
10
0.1
0.1
1.0
1.0
10.0
10.0
r (kpc)
100.0
100.0
0.1
1000.0
10
1.0
Gaspari+ 2012,2013,2014; Li & Bryan 2014a,b; Li+ 2015
300 kpc
Precipitation-Regulated Galaxies
Precipitation-Regulated Feedback
G M Voit
Gaspari+ 2012,2013,2014; Li & Bryan 2014a,b; Li+ 2015
300 kpc
Precipitation-Regulated Galaxies
Precipitation-Regulated Feedback
G M Voit
Precipitation & Galaxy Evolution
Precipitation Cycles
Li+ 2015 (in press, ApJ, arXiv:1503.02660)
G M Voit
Precipitation-Regulated Galaxies
Toward Cosmological Implementation
Meece Ph.D. Thesis
G M Voit
ρ
T
K
P
dye
tc/tff
Precipitation & Quenching
Precipitation-Regulated Galaxies
G M Voit
3
Werner+ 12, Werner+ 14
Single-Phase
Multiphase
30 kpc
Precipitation-Regulated Galaxies
Two Kinds of Massive Ellipticals
G M Voit
NCG 1399
NGC 5044
Voit+ 15 (Apr 2015, ApJL) , data: Werner+ 12,14
100
K (keV cm2)
Precipitation-Regulated Galaxies
Entropy Profiles of Ellipticals
10
NGC4472
NGC4649
NGC1399
NGC1407
NGC4261
SN Ia sweeping prevents precipitation
SN Ia heating = rad. cooling
BH feedback required
in multiphase systems
1
Requires
Chandra-like
resolution
0.1
1.0
r (kpc)
G M Voit
Single-phase ellipticals: K ≈ (5 keV cm2) rkpc
Multiphase ellipticals:
K ≈ (3.5 keV cm2) rkpc2/3
NGC4636
NGC5813
NGC5846
NGC5044
NGC6868
10.0
Voit+ 15 (Apr 2015, ApJL) , data: Werner+ 12,14
tcool/tff
100
10
1
100
tcool/tff
Precipitation-Regulated Galaxies
Precipitation Threshold
NGC4472
NGC4649
NGC1399
NGC1407
NGC4261
AGN 100x more powerful than the others!
10
G M Voit
1
NGC4636
NGC5813
NGC5846
NGC5044
NGC6868
0.1
1.0
r (kpc)
10.0
Voit+ 15 (Apr 2015, ApJL) , data: Werner+ 12,14
tcool/tff
100
10
1
100
tcool/tff
Precipitation-Regulated Galaxies
Precipitation Threshold
NGC4472
NGC4649
NGC1399
NGC1407
NGC4261
AGN 100x more powerful than the others!
10
G M Voit
1
NGC4636
NGC5813
NGC5846
NGC5044
NGC6868
0.1
1.0
r (kpc)
10.0
Precipitation & Regulation
Precipitation-Regulated Galaxies
G M Voit
4
Precipitation-Regulated Galaxies
Regulation via Precipitation
CGM
expands
cosmic
accretion
.
CGM
Min
.
Precipitation Threshold
3kT
ne(r) ≈
10 tff(r) Λ(T,Z)
Mp
wind
.
ηM*
.
ζMin
.
ζ << 1
M*
η~1
Enrichment increases cooling
and triggers feedback that
lowers CGM density
G M Voit
Precipitation-Regulated Galaxies
Regulation via Precipitation
CGM
expands
cosmic
accretion
.
CGM
Min
.
Precipitation Threshold
3kT
ne(r) ≈
10 tff(r) Λ(T,Z)
Mp
wind
.
ηM*
.
ζMin
.
ζ << 1
M*
Precipitation Rate
ρCGM rc3
Mp ~
10 tff(rc)
.
η~1
G M Voit
Reducing CGM density
reduces gas supply for
star formation
Precipitation-Regulated Galaxies
Regulation via Precipitation
CGM
expands
cosmic
accretion
.
CGM
Min
.
Precipitation Threshold
3kT
ne(r) ≈
10 tff(r) Λ(T,Z)
Mp
wind
.
ηM*
.
ζMin
.
ζ << 1
M*
Precipitation Rate
ρCGM rc3
Mp ~
10 tff(rc)
.
η~1
Abundance Saturation
G M Voit
Saturation determines
Zgas(M) and f (M)
*
.
.
.
YM – Zgas Min
Zgas ≈
*
Mgas
Enrichment ≈ Dilution
Voit+ 15 (July 2015, ApJL)
1.00
Z / ZSun
Precipitation-Regulated Galaxies
Mass-Metallicity Relation
Lower-mass systems
reach saturation at
low enrichment levels
0.10
0.01
G M Voit
104
106
108
M* / MSun
1010
Voit+ 15 (July 2015, ApJL)
1.00
f* = M* / fb M500
Precipitation-Regulated Galaxies
Stellar Baryon Fraction
Star formation rates in
low-mass systems are
limited by saturation
0.10
0.01
Higher-mass systems
transform gas into
stars more quickly
and quench sooner
G M Voit
100
vc,max (km s-1)
Voit+ 15 (July 2015, ApJL)
1011
1010
Central Galaxies of Clusters
NGC 1277 (member of Perseus Cluster)
Ellipticals
Classical Bulges
Pseudobulges
εBH = 10-3
εBH = 10-2.5
εBH = 10-2
εBH = 10-1
MBH
Precipitation-Regulated Galaxies
MBH–σv Relation
109
108
107
10
εBH MBH c2 ~ LCGM tH
6
G M Voit
100
σv,eff (km s-1)
1000
Precipitation & X-Ray Surveyor
Precipitation-Regulated Galaxies
G M Voit
5
100
K (keV cm2)
Precipitation-Regulated Galaxies
Driver 1: Hot Gas at ~100 pc Resolution
10
NGC4472
NGC4649
NGC1399
NGC1407
NGC4261
NGC4636
NGC5813
NGC5846
NGC5044
NGC6868
1
0.1
1.0
r (kpc)
10.0
G M Voit
Resolving the Bondi radius in early-type galaxies requires
Chandra-like optical quality and many photons.
Precipitation-Regulated Galaxies
Driver 2: CGM Imaging at < 0.5 keV
Anderson+ 15
ROSAT stacks of
SDSS LRGs indicate
that Lx-Mhalo relation
extends from cluster
scales down to Milky
Way scales
G M Voit
Requires Chandra-like resolution, large effective area,
low background, soft X-ray sensitivity.
Precipitation & Galaxy Evolution
What turns galaxies on and off?
Galaxies evolve in response
to atmospheric conditions
High-resolution X-ray
imaging is essential for
studying galaxy evolution
G M Voit