Dwarf galaxies in the Canes Venatici Cloud

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