H 2 ,out(lowsandtheformation ofDarkMattercores - - PowerPoint PPT Presentation

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h 2 out lows and the formation of dark matter cores
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Introduction | Simulations | Cores | Bulges| Conclusions H 2 ,out(lowsandtheformation ofDarkMattercores F . Governato - UW A. Pontzen, S.H Oh+LITTLE THINGS team, Alyson Brooks, A.Zolotov, C.

slide-1
SLIDE 1







H2,
out(lows
and
the
formation


  • f

Dark
Matter

cores


Introduction | Simulations | Cores | Bulges| Conclusions

F . Governato - UW

  • A. Pontzen, S.H Oh+LITTLE THINGS team, Alyson Brooks, A.Zolotov, C. Christensen, P

. Jonsson, P .Madau T . Quinn, J. Wadsley & the N-Body Shop collaboration

Aug
2011

slide-2
SLIDE 2

July
26,
2011

Introduction | Simulations | Cores | Bulges | Conclusions

Outline of This Talk

Understand
how
out(in)(lows

shape the
central
mass
distribution
of
galaxies using
cosmological
hydro
simulations

Compare

with
observations. Make
predictions
of

DM
Cores
 properties
vs
galaxy
stellar
mass

slide-3
SLIDE 3
  • SN
energy
coupled
to
gas
as
thermal
energy
  • Cooling
shutoff
turned
of
for
3‐8
Myrs

  • Metal
lines
cooling
at
all
temperatures
  • Resolution
50‐160pc

~

‘resolved’
SF
regions
down
to
z=0
  • Star
particles
~
1000‐10000
Msol

  • Several
million
particles
per
(main)
galaxy.


A
High
density
Threshold
for
SF
(a
clumpy
ISM)
 




is
necessary
to
form
out=lows
with

the
 























thermal
energy
approach. 
























Resolution
must
be
high!

Out(lows,
Cores
and
Bulges July
20,
2011

Introduction| Simulations | Cores | Bulges | Conclusions

GASOLINE, a treecode+SPH cosmological code: implementation of new physics and the modeling of outflows local
energy/gas
mass
ratio
suf(icient
to
unbind
gas!

slide-4
SLIDE 4

Buoyancy

July
1,
2011

Introduction| Simulations| Cores| Bulges | Conclusions

slide-5
SLIDE 5

Gas Outflows: Thermal Feedback & Buoyant Bubbles


Bulgeless,
Cored
Disk
Galaxies
in
a
CDM
Cosmology:
End
the
Small
Scales
Crisis July
1,
2011

Introduction| Simulations| Cores| Bulges | Conclusions

Cosmological Dwarf Galaxy

slide-6
SLIDE 6
  • Dwarfs
are
bulgeless
  • The
Dark
Matter
Pro(ile
is
not
‘CDM‐like’


Out(lows,
Cores
&
Bulges July
20,
2011

Introduction | Simulations | Cores | Bulges | Conclusions

The Problem with Dwarfs (1)

Dutton
et
al
‘08 Oh
et
al

‘08 DM profile slope Sersic Index

rho ~ ρ -?

slide-7
SLIDE 7

Simulating a bulgeless dwarf galaxy?

Governator,....Jonsson...
et
al
2010

  • Exponential
stellar
disk
Rd
=

1
kpc
  • Gas
rich:
HI/stars

mass
ratio
~
2
  • Thin
disk
b/a

  • Vc
=
55
km/sec
  • blue
colors
g‐r
=
0.5
  • SFH
bursty

SFR
=
0.01
sol.
masses/yr
  • just
your
regular
dwarf...

Aug,
2011

Introduction| Simulations | Cores | Bulges| Conclusions

slide-8
SLIDE 8

Out(lows,
Bulges
&
Cores July
20,
2011

Introduction| Simulations | Cores | Bulges | Conclusions

...with a Cored DM profile as the dwarfs in the THINGS survey!

Oh
et
al
2011,
AJ

..where α 
is
the
slope
of
a
power‐law
(it
to
the
DM
pro(ile

slide-9
SLIDE 9

The
Angular
momentum
distribution
of
a
simulated
bulgeless
 galaxy
(Governato
et
al
2010).
Low
angular
momentum
gas
has
been
 removed
by
out(lows.

Only
5%
of
gas
has
been
turned
into
stars.

Out(lows,
Bulges
and
Cores July
20,
2011

Introduction| Simulations | Cores| Bulges| Conclusions

Angular Momentum Distribution: A Bulgeless Galaxy P(n)

slide-10
SLIDE 10

G10,
supplemental
material


Bulgeless,
Cored
Disk
Galaxies
in
a
CDM
Cosmology:
End
the
Small
Scales
Crisis July
1,
2011

Introduction| Simulations| Cores| Bulges | Conclusions

Hi Density- Low Res 1/64 Hi Density - High Res Low Density SF threshold High Res α=-1.5 α=-0.6

slide-11
SLIDE 11

(C.Christensen
PhD
Thesis)...(ala
TGK
’09)

  • Star
Formation
regulated
by
local
H2
fraction
  • explicit
metal
dependent
H2
formation
  • H2
cooling


  • H2
destruction
by
Lyman­Werner
radiation

Out(lows,
Cores
and
Bulges July
20,
2011

Introduction| Simulations | Cores | Bulges | Conclusions

H2 in GASOLINE is here! Where/when do stars form? We have now a sample of ~ 20 galaxies Vc from 10 to 100 km/sec @z=0 resolution 50-150pc. Stars naturally form in very dense gas.

slide-12
SLIDE 12

Gas Outflows with Thermal Feedback: Temperature map

Pontzen
&
Governato
‘11

July
1,
2011

Introduction| Simulations| Cores| Bulges | Conclusions

slide-13
SLIDE 13

Thermal Heating + buoyancy

Pontzen+
FG
in
prep

Aug,
2011

Introduction| Simulations| Cores| Bulges | Conclusions

Loading Factor: 2-5

slide-14
SLIDE 14

Introduction | Simulations | Cores | Bulges | Conclusions

Back
to
cores...

slide-15
SLIDE 15

NON adiabatic, repeated gas flows transfer energy to the DM:‘The Pontzen Scheme’

Pontzen,
Governato

2011,
submitted.

High‐quality
multi‐λ
data
(THINGS
 HI,
Spitzer
3.6μm
and
optical
data)
 signi(icantly
reduce
the


  • bservational
uncertainties
and


allow
us
to
derive
reliable
dark
 matter
density
pro(iles.

The
Pontzen
Scheme July
25,
2011

Introduction| Simulations |Cores Bulges| Conclusions

Cores Cusps

slide-16
SLIDE 16

When do DM cores form?

Pontzen
&
Governato
2011,
submitted

  • The
central
density

DM
decreases
as

  • ut(lows
transfer
energy
to
the
DM.

  • This

process
is
most
active
at

4
>
z
>
1


as
SF
peaks
in
the
galaxy
progenitors.



July
20,
2011

Introduction| Simulations | Cores | Bulges| Conclusions

z=4 z=1

slide-17
SLIDE 17

THINGS

to
be
submitted
in
Aug
2011

Introduction| Simulations | Cores | Bulges| Conclusions

The Slope of Dark Matter Halos: the Effect of Gas Outflows

THINGS Out(lows
in
ultra
faint
 galaxies
are
not
suf(icient
 to
turn

cusps
into
cores the
typical
high‐z
galaxy
 seen
by
HST
should
have
 cores! Governato
Zolotov,
 Pontzen
et
al

’11
in
prep

slide-18
SLIDE 18

Introduction| Simulations | Cores | Bulges| Conclusions

Enough
predictions. How
about
the
existing
observational
 constraints?

slide-19
SLIDE 19

July
20,
2011

Introduction| Simulations | Cores | Bulges| Conclusions

The Stellar Mass - Halo Mass Relation

7 8 9 10 11 12 log Mhalo (MΟ

  • )

3 4 5 6 7 8 9 10 log Mstar (MΟ

  • )

Moster et al. (2010)

Charlie you did it first!

slide-20
SLIDE 20

Out(lows,
Cores
and
Bulges July
20,
2011

Introduction | Simulations | Cores | Bulges | Conclusions

The Problem with Dwarfs (2): The Strigari Relation

  • “a
hint
of
a
new
scale
in
galaxy
formation”













cosmic
UV
background?

  • “a
characteristic
scale
for
the
clustering
of
dark
matter”
















WDM?

Strigari..Bullock
et
al
08

slide-21
SLIDE 21

Out(lows,
Cores
&
Bulges July
25,
2011

Introduction| Simulations | Cores | Bulges| Conclusions

Simulations vs Observations: Central Total Mass vs Stellar Mass (aka the Strigari Relation) ULTRA
FAINT

From Matt Walker From Se-Heon Oh 4+
orders
of
magnitude
in
stellar
mass

slide-22
SLIDE 22

Transfer
of
energy
to
the
Dark
Matter
brings
down
Vc
at
r
<
1kpc


Bulgeless,
Cored
Disk
Galaxies
in
a
CDM
Cosmology:
End
the
Small
Scales
Crisis July
1,
2011

Introduction| Simulations | Cores | Bulges| Conclusions

Rotation Curves of Galaxies

cored cuspy

slide-23
SLIDE 23

Aug

2011

Introduction| Simulations | Cores| Bulges| Conclusions

The Problem with Dwarfs (3): Rmax vs Vmax - Boylan Kolchin..Bullock et al ‘11

slide-24
SLIDE 24

Aug

2011

Introduction| Simulations | Cores| Bulges| Conclusions

MW satellites Rmax vs Vmax Boylan Kolchin etal ‘11

Simulated Satellites

slide-25
SLIDE 25

Thermal
Feedback:
good!
 Adiabatic
out=lows:
not
so
good... RAPID

(Vout
>
Vrot)
and
repeated
 gas
removal

creates
DM

cores
 from


‘cuspy’
CDM
halos. 30
<
Vpeak
<
110
Km/sec:

cores 
Superfaint
dwarfs:

cuspy
 Out=lows/Cores

naturally
explain

 the


Stellar
mass
­
Total
mass



 
and

Rmax
­
Vmax
relations ­
Governato
et
al
2010 ­
C.Brook
2010,
MNRAS ­
Pontzen
&
Governato
2011
 (astro­ph/1106.0499) ­
Governato,
Zolotov,
Pontzen

et
 al
2011
(submit
soon!)

Aug,
2011

Introduction| Simulations| Cores| Bulges| Conclusions

Conclusions (and relevant papers)