Transcript Diapositiva 1 - Universidad de Guanajuato

Lecture 3
Distribution of Galaxies
The Local Universe





Depto. de Astronomía (UGto)
the
the
the
the
the
Milky-Way system
Andromeda system
Local Group of Galaxies
Local Supercluster
nearby superclusters
Astronomía Extragaláctica y Cosmología Observacional
 The Local Universe: Distribution of Galaxies
Small scale:
 Galaxies are not distributed at random
 Concentrations of galaxies may be groups, clusters, superclusters or filaments
 Regions with the lowest densities of galaxies are called voids
Distribution of 14650 galaxies of the catalogs UGC, ESO and MCG
http://www.eso.org/~mhilker/Gallery/gallery_lect.html
 The Local Universe: Distribution of Galaxies
Milky-Way
Distribution of 1 600 000 galaxies from 2MASS catalog
 The Local Universe: the Milky-Way system
[Faber & Gallagher 1979, ARAA 17, 135*]
Dwarf satellites
Globular Clusters (R > 20 kpc)
[W. Harris 1999, in Globular Clusters*]
 The Local Universe: the Milky-Way and its satellites
Milky Way
(2MASS)
For dSph
Scl dSph
LeoI dSph
Car dSph
LeoII dSph
SMC
Phe dIrr
Dra dSph
LMC
Sex dSph
UMi dSph
 The Local Universe: the Milky-Way and its closest satellites
Sag DEG
CMa dwarf
• Sagitarius DEG (found by stellar
brightness density investigations)
[R. Ibata, G. Gilmore & M. Irwin 1994,
Nature 370, 6486]
• Canis Majoris dwarf (found in
2MASS data – asymetries in red
giant population)
[Martin et al. 2004, MNRAS 348, 12]
 The Local Universe: the Milky-Way and its closest satellites
UMa dw
Boo dw
CVn dw
• Ursa Majoris dwarf
(overdensity of red stars in the
SDSS)
[Willman et al. 2005, ApJ 626, 85]
• Bootes & Canis Venati dwarves
(stellar overdensity on SDSS data)
[Belokurov et al. 2006, ApJ 647, L111; y Zucker et al. 2006a, ApJ 643, 103]
 The Local Universe: the Milky-Way and its closest satellites
• UMa II dwarf
(found on SDSS data, Subaru)
[Zucker et al. 2006b, ApJ 650, L41]
• Leo T dwarf (transition)
(found on SDSS data, INT)
[Irwin et al. 2007, ApJ 656, L13]
Leo T dw
 The Local Universe: the Milky-Way system
Galaxy
Alias
Milky Way
1. CMa dwarf1
--2. Vir SS2
--3. Sag DEG3
--4
4. UMa II
--5. Coma dwarf9
--6. LMC
ESO 056-G115
7. SMC
NGC 292
5
8. Boo dwarf
--9. UMi dwarf
DDO 199
10. Draco dwarf
DDO 208
11. Sculptor dwarf ESO 351-G030
12. Sextans dwarf
--13. Carina dwarf
ESO 206-G220
6
14. UMa dwarf
--15. Fornax dwarf
ESO 356-G004
16. Hercules dwarf9
--17. CVn II dwarf9
--18. Leo IV9
--7
19. CVn dwarf
--16. Leo II
DDO 93
17. Leo I
Regulus, DDO 74
18. Phoenix dwarf ESO 245-G007
19. Leo T8
--3
1
6
2
5
Position (J2000.0)
17 45 39.9 –29 00 28
07 15
–28
12 24
+00
18 55 03.0 –30 28 42
08 51 30.0 +63 07 48
12 26 59.0 +23 54 15
05 23 35.0 –69 45 22
00 52 49.0 –72 49 43
14 00 06.0 +14 30 00
15 09 10.0 +67 12 52
17 20 12.0 +57 54 55
01 00 09.0 –33 42 33
10 13 03.0 –01 36 53
06 41 37.0 –50 57 58
10 34 53.0 +51 55 12
02 39 59.0 –34 26 57
16 31 02.0 +12 47 30
12 57 10.0 +34 19 15
11 32 57.0 –00 32 00
13 28 03.5 +33 33 21
11 13 29.0 +22 09 17
10 08 27.0 +12 18 27
01 51 06.0 –44 26 41
09 34 53.4 +17 03 05
Ibata et al. 1994, Nature 370, 6486
Martin et al. 2004, MNRAS 348, 12
Willman et al. 2005, ApJ 626, 85
Duffau et al. 2005, ApJ 636, L97
Belokurov et al. 2006, ApJ 647, L111
Type
S(B)bc
Irr(p)
Irr(p)
dSph(7p)
dSph(5)
dSph(5)
SBm
Im
dSph(3p)
dSph(5)
dSph(3)
dSph(3p)
dSph(4)
dSph(4)
dSph
dSph(3)
dSph(5)
dSph(3)
dSph(2)
dSph(4)
dSph(0)
dSph(3)
dIrr/dSph
dIrr/dSph
7
4
9
8
MV
D(kpc)
Size(’)
-20.9
-14.0
8.5
8
9
24
30
44
49
58
60
69
76
78
86
87
100
131
140
150
160
220
230
251
390
420
21600
720
30 x 10
450 x 216
-13.8
-3.8
-3.7
-18.5
-17.1
-5.8
-8.9
-8.6
-9.8
-9.5
-9.4
-6.8
-13.1
-6.0
-4.8
-5.1
-7.9
-10.1
-11.9
-9.8
-7.1
[Fe/H]
–1.9
–0.5/–1.0
–1.3
650 x 550
–0.6
280 x 160
–1.2
13 x 8.7
41 x 26
–1.9/–2.2
51 x 31
–2.0
39.8 x 30.9 –1.5/–1.8
30 x 12
–1.9/–1.7
3.5 x 15.5 –1.8/–2.0
–2.0
12 x 10.2 –1.2/–1.3
8.4 x 5
12 x 11 –1.6/–1.9
9.8 x 7.4 –1.4/–1.5
4.9 x 4.1
–1.9
4.2 x 4.2
–1.6
Zucker et al. 2006a, ApJ 643, 103
Zucker et al. 2006b, ApJ 650, L41
Belokurov et al. 2007, ApJ 654, 897
Irwin et al. 2007, ApJ 656, L13
 The Local Universe: the Andromeda system
M33
M32
M31
M110
NGC 185
NGC 147
 The Local Universe: the Andromeda system
[Van den Bergh 2006, AJ 132, 1571]
 The Local Universe: the distant members (?) of the LG
Galaxy
Distant satellites
1. N6822
2. LeoA
3. Cetus dwarf
4. Tucana dwarf
5. WLM
6. Aquarius dwarf
7. Sag DIG
8. Gr8
9. UKS 2323-326
Antlia-Sextans Group
10. NGC 3109
11. Antlia
12. Sex A
13. Sex B
Alias
DDO 69
DDO 221
DDO 210
DDO 155
UGCA 438
Position (J2000.0)
Type
Irr
dIrr
dSph
dSph
Irr
Irr
dIrr
dIrr
dIrr
Irr
dSph
dIrr
dIrr
MV
D(kpc)
-16.0
-11.5
-10.1
-9.6
-14.4
-10.9
-12.0
-10.2
0.50
0.69
0.78
0.87
0.95
0.95
1.18
1.20
-10.8
-14.2
-13.8
1.30
1.30
1.30
1.30
Size(’)
[Fe/H]
-1.7
-1.5
-1.8
-1.9
-1.2
 The Local Universe: The Local Group of Galaxies
 The Local Universe: The Local Group of Galaxies
 The Local Universe: The Local Group of Galaxies
[van den Bergh 1999, A&AR 9, 273]
 The Local Universe: The Local Group of Galaxies
Virial mass:
MLG ≈ (7.5/G) <σ>2 RH
= (7.5/G) (61 km/s)2 (350 kpc)
 2.3  1012 M
Zero-velocity surface radius:
 radius beyond which galaxies participate in the
Hubble expansion (or distance from which a
free-falling body, beginning at rest, would take
the age of the Universe to reach the center)
[Lynden-Bell 1981, Observatory 101, 111]
tcol = ¼ √ (3π / 2Gρ)
= ¼ √ (2 π2 R3 / GM)
 R3 = (8/ π2) GM tcol2
 considering: MLG = 2.3  1012 M
and
tcol = tH ≈ 14 Ga
RLG  1.2 Mpc
 The Local Universe: The Local Group of Galaxies
[van den Bergh 1999, A&AR 9, 273]
[van den Bergh 2000, PASP 112, 529] 
 The Local Universe: The vicinity of the LG
AntliaSextans
Maffei
Sculptor
[Karachentsev et al. 2004, AJ 127, 2031]
 The Local Universe: The vicinity of the LG
H0 = 72 km s-1 Mpc-1
IC 342
M81
M31
CnV I
NGC 253
M83
CenA
[Karachentsev et al. 2005,
AJ 129, 178] 
 The Local Universe: The Local Supercluster
• discovery of the Local Supercluster
[G. de Vaucouleurs 1953, AJ 58, 30]
 The Local Universe: The Local Supercluster
[Sparke & Gallagher III,
Galaxies in the Universe:
an Introduction*]
[B. Tully 1982,
ApJ 257, 389] 
 The Local Universe: Nearby Superclusters
• the Coma-Leo Supercluster
[Gregory & Thompson 1978, ApJ 222, 784 ]
• the Perseus-Pisces Supercluster
[Wegner, Haynes & Giovanelli 1993, AJ 105, 1251]
 The Local Universe
[Fairall 1998, Large
Scale Structures
in the Universe*]
 The Local Universe
[M. Hudson 1993,
MNRAS 265, 43]
http://www.atlasoftheuniverse.com/ 
 The Local
Universe
 300 Mpc
 600 Mpc
z = λo – λe = H0  d
λe
c
 4 Gpc
The
“Observable
Universe”
Age of the
Universe
Quasars