Post on 04-Jan-2016
description
Dwarf galaxies in the Canes Venatici Cloud
Roman UKLEIN,
Dmitry MAKAROV and
Lidia MAKAROVA
SAO RAS, RussiaNizhny Arkhyz, KChR, Russia
September, 14 – 18, 2009
NDG 2009
Distribution of the galaxies with VLG<550 km/s (Local Volume)
2h4h6h8h10h12h14h16h18h20h22h
0
+90
-90
50 100 150 200 250 300 350 400 450 500
Canes VenaticiCanes Venatici
VLG, km/s
VirgoVirgo
M81M81
CenACenA
Radial velocity histogram in the CVn region
100 200 300 400 500 600 700 800 900 10000
2
4
6
8
10
12
14
16
18
VLG
N
Distribution of the galaxies in the CVn
M94
25
30
35
40
45
50
55
11.5h
12h12.5h13h13.5h
150 200 250 300 350VLG, km/s
Advanced TRGB-method (Makarov+, 2006)
-1 0 1 2 3
19
20
21
22
23
24
25
26
F606W-F814W
F81
4W
DDO 099
23.14
19 20 21 22 23 24 25 26
0
0.5
1
19 20 21 22 23 24 25 26
-1.5
-1
-0.5
0
0.5
F814W
22 22.5 23 23.5 24 24.510
1
102
103
F814W
Color-Magnitude Diagrams
-1 0 1 2 3
18
19
20
21
22
23
24
25
26
27
28
F606W-F814W
F81
4W
UGC 8215
24.17
-1 0 1 2 3
19
20
21
22
23
24
25
26
F606W-F814W
F81
4W
UGC7298
24.17
-1 0 1 2 3
18
19
20
21
22
23
24
25
26
F606W-F814W
F81
4W
NGC4449
24.14
good badgood
Distance Errors
~ 5-6% up to 25%good bad
3D structure:
View on Supergalactic plane
-0.5
0
0.5
1
1.5
2
1.5 2 2.5 3 3.5 4 4.5 5
IC4182
NGC3738
NGC4214
NGC4244
NGC4449
M94
NGC5204
Super
Gal
actic
X (M
pc)
SuperGalactic Y (Mpc)
0
0.2
0.4
0.6
0.8
1
SGZ, Mpc
Old Hubble Diagram
0 1 2 3 4 5 6 7 80
100
200
300
400
500
600
Distance (Mpc)
VLG
(km
/s)
VLG
= 72 D
0 1 2 3 4 5 6 7 80
100
200
300
400
500
600
Distance (Mpc)
VLG
(km
/s)
VLG
= 72 D
New Hubble Diagram
0 1 2 3 4 5 6 7 80
100
200
300
400
500
600
Distance (Mpc)
VLG
(km
/s)
VLG
= 72 D
Vmed
= 297 km/s
R0 ~ 1 Mpc
New Hubble Diagram
The Mass Estimation
MethodTotal Mass,
1012 Msun
Zero-Velocity Surface 2.1
Virial Theorem 4.9
Projected Mass Estimator* 2.7
Average Mass Estimator* 3.0
Median Mass Estimator* 4.6
*Heisler, Tremaine & Bahcall (1985)
~3.5~3.5
Mass-to-Luminosity ratio
M / LM / LBB ~~ 100-200100-200
LB,total = 2.3·1010Lsun
Conclusions:
• The homogeneous distances to the galaxies in the CVn I Cloud were determined using advanced TRGB method.
• We clarify the spatial structure: the cloud is divided on the core and foreground outskirt. What’s farther?
• The dynamical mass of the CVn I Cloud much the same as masses of groups like Local Group.
TT HH AA NN K K YY OO U U FF OO R R YY OO UU R R
AA TT TT EE NN TT II OO NN !!
Properties of the CVn I galaxies
D
W
A
R
F
S
M/L estimation for nearby groups
Group M/L
Milky Way/M31 121/10.1 = 12
M81/NGC 2403 169/6.1 = 28
Cen A/M83 292/7.9 = 37
CVn Cloud 300/2 = 150
Luminosity Function
-22 -20 -18 -16 -14 -12 -10 -80
1
2
3
4
5
6
7
8
Mb, mag
N
Distance-Luminosity
-20 -18 -16 -14 -12 -10 -81.5
2
2.5
3
3.5
4
4.5
5
5.5
12.513 13.514 14.515 15.516 16.517
Mb, mag
D,
Mpc
NGC 4214