Leo Cloud

The Leo II Groups,^[6] Leo II Cloud,^[1] or simply the Leo Cloud^[5][7][8] is a galaxy filament^[8] consisting of at least 18 galaxy groups.^[5][7] It is located approximately 86 Mly (26 Mpc) from the Solar System.^[2] The Leo Cloud in supergalactic SGY coordinates is physically behind the Virgo Cluster.^[9] Eventually, over the next Hubble time, the galaxy groups that make up the Leo II Cloud will infall and merge with the Virgo Cluster.^[10]

Leo Cloud
The Leo II Groups of galaxies
Observation data (Epoch )
Parent structure	Virgo Supercluster[1]
Major axis	Leo Cloud: 15.4 Mpc (50 Mly)[1] Leo II A Filament : 16.0 Mpc (52 Mly) [2] Leo II B Filament : 15.5 Mpc (51 Mly) [2]
Minor axis	7.9 Mpc (26 Mly)[1]
Redshift	1,200 km/s [3]
Distance	Leo Cloud: 26.35 Mpc (86 Mly) (Distance based on the average of the distances of the Leo II A and B Filaments)[2] Leo II A Filament : 26.30 Mpc (86 Mly) [2] Leo II B Filament : 26.40 Mpc (86 Mly) [2]
Other designations
Leo II Cloud Complex,[4] Leo II Cloud,[1] Leo Cloud,[5] Leo II Groups[6]

The Leo Cloud, along with the Crater Cloud which contains the NGC 4038 Group, is actually the same branch of a larger galaxy filament that extends from the Centaurus Cluster through the Virgo Cluster and continues through the Ursa Major Cluster, known as the Virgo Strand. The Virgo Strand is the main component of the Virgo Supercluster and is made of two branches with the lower branch consisting of the Leo and Crater clouds, while the upper branch^{[clarification needed]} is known as the Virgo Southern Extension or Virgo II Groups.^[8]

The Leo Cloud itself is actually composed of two filaments, the Leo II A and Leo II B filaments. The Leo II A filament consists of the majority of the cloud, while the Leo II B filament consists of a sparse region of the cloud.^[2]

The Leo Cloud, like the Virgo III Cloud, is prolate and points toward the Virgo Cluster.^[1]

List of groups

Below is a list of groups in the Leo Cloud according to astronomer Brent Tully.^[5][7]

Column 1: The name of the group in Tully's NBGG^[5][7]

Column 2: The right ascension for epoch 2000.

Column 3: The declination for epoch 2000.

Column 4: Number of members of the group.

Column 5: Brightest member of the group

Column 6: Redshift of the group.

Column 7: Distance of the group (Millions of light-years).

Column 8: Cross-Identifications with other catalogs.

(Sources for data columns:^{[5][7][11][12][13]})

Groups within the Leo Cloud

Name of group	R.A. (J2000)	Dec. (J2000)	Number of members	Brightest member	Redshift	Distance (Mly)	Cross-ID
NBGC 21-1	11h 24m 25.6s[14]	17d 22m 44s[14]	11 (Tully) 11 (Fourque) 8 (Garcia) 10/16/16 (Giuricin)	NGC 3607[13]	0.004000[14]	68[14]	NGC 3607 Group,[15][11][12][13] Leo II Group, GHCG 77, TG 36, DV 49, [FWB89] GrG 48, [N93] 65, [N93] 66,[15] NGC 3626 Group,[11] NGC 3507 Group, LGG 228, NGC 3686 Group, LGG 237,[12] NOGG H 527, NOGG P1 532, NOGG P2 542[13]
NBGC 21-2	11h 02m 47.3s[16]	17d 59m 22s[16]	3 (Tully)	NGC 3501[7]	0.003769[16]	66[16]
NBGC 21-3	10h 50m 45.0s[17]	17d 20m 49s[17]	10 (Tully) 6 (Fourque) 5 (Garcia) 10/13/13 (Giuricin)	NGC 3370[7]	0.004273[18]	72[18]	NGC 3370 Group,[11][12] LGG 219,[12] NGC 3507 Group, NOGG H 497, P1 512, P2 522[13]
NBGC 21-4	11h 39m 35.688s[13]	11d 47m 29.33s[13]	2 (Tully) 2 (Giuricin)	NGC 3810[13]	0.003309[19]	60[19]	NGC 3810 Group, NOGG P1 561, NOGG NOGG P2 570[13]
NBGC 21-5	10h 44m 0.8.6s[20]	13d 40m 30s[20]	3 (Tully) 3 (Fourque) 4 (Garcia) 4 (Giuricin)	NGC 3338[13]	0.004286[20]	73[20]	NGC 3338 Group,[11][12][13] LGG 219,[12] NOGG H 480, NOGG P1 498, NOGG P2 501[13]
NBGC 21-6	10h 21m 35.2s[21]	21d 07m 41s[21]	12 (Tully) 5/8 (Fourque) 13 (Garcia) 8/7/7 (Giuricin)	NGC 3190[13]	0.004670[21]	77[21]	NGC 3190 Group, NGC 3227 Group,[11] LGG 194,[12] NOGG H 454, NOGG P1 469, NOGG P2 476[13]
NBGC 21-7	11h 03m 36.558s[13]	28d 00m 22.56s[13]	2 (Tully) 6 (Garcia) 2 (Giuricin)	NGC 3504[13]	0.005074[22]	82[22]	NGC 3504 Group,[12][13] LGG 227,[12] NOGG P1 519, NOGG P2 529[13]
NBGC 21-8	10h 28m 55.4s[23]	28d 47m 52s[23]	4 (Tully) 4 (Fourque) 5 (Garcia) 5 (Giuricin)	NGC 3254[7]	0.004610[23]	75[23]	NGC 3254 Group,[12][13] LGG 197,[12] NOGG H 465, NOGG P1 479, NOGG P2 486[13]
NBGC 21-9	10h 51m 46.7s[24]	32d 51m 31s[24]	4 (Tully) 5 (Fourque) 6 (Garcia) 4 (Giuricin)	NGC 3430[13]	0.005000[24]	80[24]	NGC 3396 Group,[11][12] LGG 218,[12] NGC 3430 Group, NOGG H 490, NOGG P1 500, NOGG P2 510[13]
NBGC 21-10	10h 13m 57.0s[25]	03d 23m 20s[25]	5 (Tully) 3 (Fourque) 5 (Garcia) 4 (Giuricin)	NGC 3169[13]	0.003599[25]	64[25]	NGC 3166 Group,[11] NGC 3169 Group,[12][13] LGG 192,[12] NOGG H 446, NOGG P1 463, NOGG P2 470[13]
NBGC 21-11	11h 20m 41.4s[26]	03d 15m 19s[26]	5 (Tully) 5 (Fourque) 6 (Garcia) 3 (Giuricin)	NGC 3640[13]	0.004203[26]	72[26]	NGC 3640 Group,[11][12][13] LGG 233,[12] NOGG H 522, NOGG P1 536, NOGG P2 546[13]
NBGC 21-12	09h 49m 43.946s[13]	32d 53m 48.99s[13]	10 (Tully) 3 (Fourque) 4 (Giuricin)	NGC 3003[13]	0.004937[27]	78[27]	NGC 2964 Group,[11] NGC 3003 Group, NOGG H 420, NOGG P1 433, NOGG P2 442[13]
NBGC 21-13	09h 50m 54.242s[28]	28d 32m 57.12s[28]	2 (Tully) 2 (Giuricin)	NGC 3026[13]	0.004923[28]	79[28]	NGC 3026 Group, NOGG H 426, NOGG P1 440, NOGG P2 448[13]
NBGC 21-14	09h 59m 53.783s[13]	37d 16m 13.72s[13]	2 (Tully) 2 (Giuricin)	UGC 5349[13]	0.004590[29]	73[29]	UGC 5349 Group, NOGG P1 452, NOGG P2 459[13]
NBGC 21-15	09h 24m 18.857s[13]	34h 30m 45.59s[13]	2 (Tully) 3 (Giuricin)	NGC 2859[13]	0.005631[30]	86[30]	NGC 2859 Group, NOGG H 391, NOGG P1 403, NOGG P2 412[13]
NBGC 21-16	09h 17m 27.179s[13]	41h 59m 50.20s[13]	2 (Tully) 2/3/3 (Giuricin)	NGC 2798[13]	0.005801[31]	87[31]	NGC 2798 Group, NOGG H 385, NOGG P1 395, NOGG P2 405[13]
NBGC 21-17	09h 23m 14.210s[13]	40h 09m 52.75s[13]	3 (Tully) 2/3/2 (Giuricin)	NGC 2844[13]	0.004937[32]	79[32]	NGC 2852 Group, NOGG H 389, NOGG P1 401, NOGG P2 410[13]
NBGC 21-18	09h 12m 35.3s[33]	34h 59m 06s[33]	5 (Tully) 3 (Garcia) 4/4/3 (Giuricin)	NGC 2770[13]	0.007000[33]	104[33]	RSCG 30,[34] NGC 2778 Group,[12][13] LGG 171,[12] NGC 2770 Group, NOGG H 381, NOGG P1 391, NOGG P2 401[13]

See also

• M96 Group
• Virgo II Groups
• Virgo III Groups