What’s New with Peculiar Velocities?

hundreds of 5% distances within 6 Mpc

galaxies gather in groups; few are isolated

modest group masses; don’t account for much of mean matter density

small dispersion in velocities on ~5 Mpc scales

dynamically evolved clusters with large M/L

significant streaming - local velocity anomaly

suggests the existence of considerable mass associated with filaments but outside of groups

hundreds of 5% distances within

6 Mpc

marginal at 5 Mpc

OK at 8 Mpc

good at 3 Mpc

good distances 2

a group of dwarf galaxies at 3 Mpc

good distances 3

a group at almost 8 Mpc with a large peculiar velocity

VLG = 180 km/sVpec= -380 km/s

good distances 4

all-sky inventory off POSS for dwarfs by Karachentseva and Karachentsev ; HI follow-up provides velocities

about 200 of ~400 suspected to lie within ~7 Mpc now have good distances

if you are ever on the HST TAC, give us time to do more!

galaxies gather in groups; few are isolated

galaxies gather in groups

2-point correlation

signal dominated by groups like Local Group

only dwarf groups

the local group

MWM31

31

quasi-virialized infall

galaxies at 1.1 - 3.2 Mpc |b|>30o [66 Mpc3]

beyond Local Group Mpc kpc14+12 N3109 1.33 -15.5 310 Sex B 1.39 -14.0 450 Sex A 1.40 -13.8 210 Antlia 1.25 -9.3 350 KKH60 ? -7.8 ?

2x1011 M in 0.4 Mpc3

14+13 N 55 2.19 -17.9 190 N 300 1.87 -17.5 320 E407-18 2.14 -12.9 400 E410-05 1.92 -11.6 200 E294-10 2.00 -11.0 200 ----------------------- IC5152 2.07 -15.6 820

9x1011 M in 0.3 Mpc3

14+7 N4214 2.83 -17.1 U7577 2.55 -14.2 N4163 2.96 -13.8 U6817 2.56 -13.5 N3741 3.13 -13.2 U8508 2.59 -13.0 UA276 2.84 -11.7

14+8 U9240 2.79 -14.2 460 U8760 3.24 -13.2 210 U8651 3.02 -12.9 180 U8833 3.20 -12.4 260

dregs U9128 2.24 -12.5 300 U8091 2.10 -12.0 490 KKH86 2.52 -10.3 670 KK230 1.90 -8.6 700 KKR25 1.85

modest group masses Omegam ~0.27

The mass in nearby groups of spirals is well below the level needed to explain the cosmic mean

density

small dispersion in velocities on ~5 Mpc scales

dynamically evolved environments with large Vpec

V=1779 km/s

V= 558 km/s

significant streaming - the local velocity anomaly

Milky Way

14+19 groupVLG=182 km/s

-380 km/s

-460 km/s

plane of local filament

Numerical Action Models

Best models:

• only ~1/3 of mass distributed like galaxies

• considerable mass smoothly distributed on 5-10 Mpc scale

conclusion:

low velocity dispersion locally [~30 km/s] modest M/L in groups of spiral galaxies [< 100] large streaming motions between filaments [several x 100 km/s] global M/L assignments in NAM models in reasonable agreement with concordance model [~200]

Suggests the existence of considerable mass associated with filaments but outside of groups