2001AJ....121..649G


C.D.S. - SIMBAD4 rel 1.7 - 2020.03.28CET22:57:07

2001AJ....121..649G - Astron. J., 121, 649-661 (2001/February-0)

Deviations from the fundamental plane and the peculiar velocities of clusters.

GIBBONS R.A., FRUCHTER A.S. and BOTHUN G.D.

Abstract (from CDS):

We fit the fundamental plane, FP, to over 400 early-type galaxies in 20 nearby clusters (cz∼4000-11000 km.s–1), using our own photometry and spectroscopy, as well as measurements culled from the literature. We find that the quality of fit, rms(logσ), to the average fundamental plane, <FP>, varies substantially among these clusters. A statistically significant gap in the distribution of rms(logσ) separates the clusters that fit <FP> well from those that do not. These two subgroups are of roughly equal size (11 low-rms clusters and nine high-rms clusters). The mean redshifts of the two subsamples are 6700 and 8000 km.s–1, respectively, and both samples show a mean peculiar velocity of zero. However, the nine high-rms(logσ) clusters exhibit a scatter about the mean peculiar velocity of 785±200 km.s–1, similar in amplitude to large-scale motions reported by other observers. In contrast, the other 11 clusters exhibit significantly lower scatter, equal to 245±55 km.s–1. Assuming early-type galaxies in clusters are drawn from a single underlying population, there should be no correlation between the scatter in peculiar velocity and rms(logσ). While the source of the high values of rms(logσ) exhibited in this subset of clusters is not entirely known, there is some indication that it is an intrinsic cluster property, possibly related to the presence of significant substructure. For example, we find that all X-ray-bright clusters in our sample fit the <FP> well, i.e., they exhibit low values for rms(logσ). The evidence suggests that all-sky surveys that mix together both classes of clusters, as characterized by rms(logσ), may artificially inject signal into the observed peculiar velocity field. We therefore suggest that a prefilter such as the X-ray luminosity of clusters or FP scatter be used to select clusters to derive relative distances via the FP. When such a prefilter is applied to our sample a relatively quiescent Hubble flow is revealed.

Abstract Copyright:

Journal keyword(s): Cosmology: Cosmic Microwave Background - Cosmology: Distance Scale - Galaxies: Clusters: General - Galaxies: Distances and Redshifts - Galaxies: Fundamental Parameters

Status at CDS:  

CDS comments: T.2 : Cluster J8 = [WCB96] J8, Cluster 7S 21 = [FWB89] 21, HMS 0122 = H MS 0122+3305

Simbad objects: 20

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Number of rows : 20

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 NAME NGC 80 Group * 00 20 43.1248080085 +22 08 42.433398593   12.73 12.50     ~ 15 1
2 NAME Pisces Cluster ClG 00 58 25.0 +30 39 11           ~ 119 1
3 ClG 0122+3305 ClG 01 25 +33.4           ~ 12 1
4 ACO 194 ClG 01 26 01.3 -01 22 02           ~ 328 2
5 ACO 262 ClG 01 52 50.4 +36 08 46           ~ 647 1
6 ACO 347 ClG 02 25 50 +41 52.5           ~ 142 1
7 CAN 16 ClG 02 30.2 +23 09           ~ 12 1
8 ACO 400 ClG 02 57 37.4 +06 00 45           ~ 380 3
9 ACO 426 ClG 03 19 47.2 +41 30 47           ~ 1917 1
10 ACO 539 ClG 05 16 35.1 +06 27 14           ~ 240 2
11 ACO 3381 ClG 06 09.9 -33 36           ~ 74 2
12 NAME Hydra I Cluster ClG 10 36 36.0 -27 31 04           ~ 769 1
13 ACO 1185 ClG 11 10 31.4 +28 43 39           ~ 242 1
14 ACO 1656 ClG 12 59 48.7 +27 58 50           ~ 4162 2
15 NAME IC 4329 Group GrG 13 48 36.4 -30 30 13           ~ 130 2
16 ACO 2063 ClG 15 23 01.8 +08 38 22           ~ 367 2
17 ACO 2151 ClG 16 05 15.0 +17 44 55           ~ 549 3
18 ACO 2199 ClG 16 28 37.0 +39 31 28           ~ 1093 1
19 ACO 2634 ClG 23 38 18.4 +27 01 37           ~ 475 2
20 ACO 4038 ClG 23 47 31.1 -28 12 10           ~ 309 3

    Equat.    Gal    SGal    Ecl

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2020.03.28-22:57:07

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