dark matter in galaxies paolo salucci (sissa). dennis: rotation curves, dark matter, nature of, role...
Post on 14-Dec-2015
217 Views
Preview:
TRANSCRIPT
DARK MATTER IN GALAXIES
Paolo Salucci (SISSA)
Dennis: Rotation Curves, Dark Matter, Nature of, Role of Baryons.
Importance of the topics but low interest from Scientific Community
Persic, M., S. P., 1988, MNRAS, 234 131
Dark and visible matter in spiral galaxies
Persic, M.; S. P., Stel, F. 1996 MNRAS, 281, 27
The universal rotation curve of spiral galaxies - I. The dark matter connection
Gentile, G.; S. P., Klein, U. 2004 MNRAS, 351, 903
The cored distribution of dark matter in spiral galaxies
S.P + 2007 MNRAS
The universal rotation curve of spiral galaxies out the virial radius II
S.P. ...... ADS reviews
Central surface brightness vs magnitude
The Realm of Galaxies
15 mag range, 4 types, 16 mag arsec-2.range
Stellar distribution L(R/RD)/LT is independent of luminosity
The light surface profile I(r) = I0exp (-R/RD).
A mass lenght-scale
luminosity independent?
1000 objects
Colo
rs a
re r
ad
ially
con
stan
t
3RD
RTF: magnitude vs log velocity @ different radii xi RD, [ xi=0.5,1,…5]
3 samples (600, 89, 78) M =ai + bi log V(xi)
No relationship ↔ V does not trace the mass
Vmax
Does the kinematics probe the mass distribution of galaxies ? Yes.
• Radial Tully Fisher
• Inner mass distribution
0.0 0.5 1.0 1.5 2.0 2.5 3.0
0
50
100
150
200
250
V
R/Rd
UGC2405
Radial TF
Slope and scatter of the TF-relations:
MB = ai + bi log V(xi)
The slope increases from -4 to -8.
No change in slope ↔ no DM or a constant fraction of DM
The minimum scatter 0.2 mag at 2.2 RD
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0-1
-2
-3
-4
-5
-6
-7
-8
-9
86 galaxies (Courteau) 967 galaxies (Mathewson)
Slo
pe
R/Rd
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
86 galaxies (Courteau) 967 galaxies (Mathewson)
sca
tter
R/Rd
MODEL
V traces the potential
DM emerges at large radii
Modelling the very inner circular velocities: light traces the mass
Phenomenology of spiral kinematics
The rotation curves 3200 coadded individual
PSS
C+06
RC slopes vary among galaxies and within them.
They indicate the presence and the amount of dark matter.
At 3 disk length scales
The URC concept
➲ @ fixed L and x=R/RD, the Cosmic Variance of V(x,L) is one order of magnitude smaller than the variations that:
➲in each galaxy, V(x) shows as x varies.
➲V(x) shows, @ each x, in galaxies of different L
3.avi
../Desktop/3.avi
The URC
Rotation curve modelling.
V d is k R➲ : from I-band photometry
➲ : from HI observations
➲
• dark halos with constant density cores
• dark halos with “cusps” (NFW, Moore)
• HI-scaling
• MOdified Newtonian Dynamics
..t4bt5b
V h a lo R
V g a s R
V tot2 V DM
2 V disk2 V gas
2
NFW Halos
Burkert Halos
cored vs cusped
VNFW fits uniquely a rotation curve
Modelling the Universal Rotation Curve
rotation velocity
stellar contribution
dark matter contribution
Stars
DM
LM
A family governed by luminosity
DM
fra
ctio
n
core radiushalo central density
luminosity
The role of the slope of the RC
Halo central density vs core radius scaling r 0 =10-23 (r0 /kpc)-1 g/cm3
dSph
B
URCWL
Virial halo masses
andHMF M h dM h A M h
1.84 dM h
HMF M h dM h dM bdM b BMF M b dM b
Christiane Frigerio Martins
Weak lensing
With a density profile we model the tangential shear
Obtain the structural free parameters.
Same results as those obtained from RCs.
Burkert profile provides excellent fit, better than NFW.
NFW
B
DM halo density: observations vs simulations
URCL
NFW
URCH
The UNIVERSAL velocity CURVE
Dark halos from simulations
Halos form hierarchically bottom-up via grav. amplifications of initial density flucts. Most
evident property: CENTRAL CUSP
NFW r s
r r s 1 r r s2
M vir43 vir u Rvir
3cvir Rvir r s 9.7 M vir 1012 M un
0.09V vir
2 GM vir Rvir
cuspy NFW density profiles disagree with observed kinematics.
comparison galaxy by galaxy and of coadded kinematics.
The cusp vs core issue
NFW HALOS
• Fit badly the RCs
• Unphysically too low stellar mass-to-light ratios
• Unphysically too high halo masses
Navarro, Frenk & White, ApJ 462, 563 (1996)
Bullock et al., MNRAS 321, 559 (2001)
Moo
re, N
atur
e 37
0, 6
29 (1
994)
Krav
tsov
et a
l., A
pJ 5
02, 4
8 (1
998)
Salu
cci &
Bur
kert,
ApJ
537
, L9
(200
0)
de B
lok,
McG
augh
& R
ubin
, AJ
122
, 239
6 (2
000)
Salu
cci M
NR
AS, 3
20, 1
(200
1)
Mar
ches
ini,
D'O
nghi
a, C
hinc
arin
i et a
l. ,A
pJ 5
75, 8
01 (2
002)
de B
lok
& Bos
ma,
A&A
385
, 816
(200
2)
Salu
cci,
Wal
ter &
Bor
riello
, A&A
409
, 53
(200
3)
Don
ato,
Gen
tile,
Sal
ucci
MN
RAS
, 353
, L17
(200
4)
Gen
tile,
Sal
ucci
, Kle
in e
t al.,
MN
RAS
351
, 903
(200
4)
Gen
tile,
Bur
kert,
Sal
ucci
et a
l. A
pJ 6
34, L
145
(200
5)
Spek
kens
& G
iova
nelli
AJ
132,
142
6 (2
006)
Gen
tile,
Sal
ucci
, Kle
in, e
t al.
MN
RAS
, 375
, 199
(200
7)
Salu
cci,
Lapi
, Ton
ini
et a
l M
NR
AS 3
78, 4
1 (2
007)
Kuzi
o de
Nar
ay, M
cGau
gh &
de
Blok
, ApJ
676
, 920
(200
8)
de B
lok,
Wal
ter,
Brin
ks e
t al.
AJ 1
36, 2
648
(200
8)
Span
o, M
arce
lin, A
mra
m e
t al.
MN
RAS
383
, 297
(200
8)
Wal
ter,
Brin
ks, d
e Bl
ok e
t al.
AJ,
136,
256
3 (2
008)
Trac
hter
nach
, de
Blok
, Wal
ter,
et a
l. AJ
, 136
, 272
0 (2
008)
van
Eym
eren
, Tra
chte
rnac
h, K
orib
alsk
i, et
al.
arXi
v:09
06.4
654
A test case: ESO 116-G12
gas
stars
halo
Cored halos the best fits
50 objects investigated
NFW inconsistent
Theory Obis ssw
Obs Theory
DDO 47: a decisive case
NFW
Results fromTrieste: analysis of highquality RCs
URC fits to RCs
DDO 47
Borriello & Salucci, MNRAS 323, 285 (2001)
Gentile, Tonini & Salucci, A&A 467, 925 (2007)Gentile et al., ApJ 634, L145 (2005)
DDO 47: non circular motions?
R
V (
min
or a
xis)
Triaxial halos predictions
A Universal Mass Profile Walker et al 09Dwarf Spheroidal Galaxies
LCDM Universal Rotation Curve from NFW profile and MMW theory
➲ AN INTRIGUING PROPERTY
A matter enigma
DM in early-types: weak+strong lensingDM in early-types: weak+strong lensing22 bright E/S0s at z ~ 0.2 (SLACS: Gavazzi et al. 2007)
DARK MATTER IS PRESENT IN GALAXIES
IT IS STRONGLY RELATED TO THE LUMINOUS MATTER
THERE IS A SOLID EMPIRICAL SCENARIO
We can uniquely mass model a RC
disk-halo components, known surf phot, reliable V(R) and dV/dR, resolution ~ 0.3 RD
A way out? angular momentum exchange between baryons and DM Tonini Lapi Salucci
cusp
core
top related