Relation Of Early-type Galaxies Research Articles

MaNGA DynPop – III. Stellar dynamics versus stellar population relations in 6000 early-type and spiral galaxies: Fundamental Plane, mass-to-light ratios, total density slopes, and dark matter fractions

ABSTRACT We present dynamical scaling relations, combined with the stellar population properties, for a subsample of about 6000 nearby galaxies with the most reliable dynamical models extracted from the full Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) sample of 10 000 galaxies. We show that the inclination-corrected mass plane for both early-type galaxies (ETGs) and late-type galaxies (LTGs), which links dynamical mass, projected half-light radius Re, and the second stellar velocity moment σe within Re, satisfies the virial theorem and is even tighter than the uncorrected one. We find a clear parabolic relation between $\lg (M/L)_{\rm e}$, the total mass-to-light ratio (M/L) within a sphere of radius Re, and $\lg \sigma _{\rm e}$, with the M/L increasing with σe and for older stellar populations. However, the relation for ETGs is linear and the one for the youngest galaxies is constant. We confirm and improve the relation between mass-weighted total density slopes $\overline{\gamma _{_{\rm T}}}$ and σe: $\overline{\gamma _{_{\rm T}}}$ become steeper with increasing σe until $\lg (\sigma _{\rm e}/{\rm km\, s^{-1}})\approx 2.2$ and then remain constant around $\overline{\gamma _{_{\rm T}}}\approx 2.2$. The $\overline{\gamma _{_{\rm T}}}\!-\!\sigma _{\rm e}$ variation is larger for LTGs than ETGs. At fixed σe the total density profiles steepen with galaxy age and for ETGs. We find generally low dark matter fractions, median fDM(<Re) = 8 per cent, within a sphere of radius Re. However, we find that fDM(<Re) depends on σe better than stellar mass: dark matter increases to a median fDM(<Re) = 33 per cent for galaxies with $\sigma _{\rm e}\lesssim 100$ km s−1. The increased fDM(<Re) at low σe explains the parabolic $\lg (M/L)_{\rm e}\!-\!\lg \sigma _{\rm e}$ relation.

Estimating the metallicity of star-forming early-type galaxies

ABSTRACT We derive data for 4615 star-forming early-type galaxies (ETGs), which come from a cross-match of the Galaxy Zoo and the catalogue of the Max Planck Institute for Astrophysics–Johns Hopkins University (MPA–JHU) emission-line measurements for the Sloan Digital Sky Survey Data Release 7. Our sample is distributed mainly at $-0.7< \log({\rm SFR}/({\rm M}_{\odot }\, {\rm yr}^{-1})) < 1.2$, and the median value of our star formation rates (SFRs) is slightly higher than that shown in Davis & Young. We show that there is a significant trend of lower/higher stellar mass ETGs having lower/higher SFRs, and we obtain our sample best fit of $\log(\rm SFR/(M_{\odot} \rm yr^{-1}))=(0.74\pm0.01)\rm log(M_{*}/M_{\odot})-(7.64\pm0.10)$. We find the same slope as found by Cano-Díaz et al. In our star-forming ETG sample, we demonstrate clearly the correlation of the stellar mass–metallicity (MZ) relation. We find that higher metallicity measurements may be introduced by the diffuse ionized gas, when the D16, Sanch18 and Sander18 indicators are used to calibrate the metallicity of ETGs. We show the relations between the SFR and 12 + log(O/H) with different metallicity estimators, and we suggest that their correlations may be a consequence of the SFR–stellar mass and MZ relations in ETGs.

The parallelism between galaxy clusters and early-type galaxies

Context. This is the second work dedicated to the observed parallelism between galaxy clusters (GCs) and early-type galaxies (ETGs). The focus is on the distribution of these systems in the scaling relations (SRs) observed when effective radii, effective surface brightness, total luminosities, and velocity dispersions are mutually correlated. Aims. Using the data of the Illustris simulation we speculate on the origin of the observed SRs. Methods. We compare the observational SRs extracted from the database of the WIde-field Nearby Galaxy-cluster Survey with the relevant parameters coming from the Illustris simulations. Then we use the simulated data at different redshift to infer the evolution of the SRs. Results. The comparison demonstrate that GCs at z ∼ 0 follow the same log(L)−​log(σ) relation of ETGs and that both in the log(⟨I⟩e)−​log(Re) and log(Re)−​log(M*) planes the distribution of GCs is along the sequence defined by the brightest and massive early-type galaxies (BCGs). The Illustris simulation reproduces the tails of the massive galaxies visible both in the log(⟨I⟩e)−​log(Re) and log(Re)−​log(M*) planes, but fails to give the correct estimate of the effective radii of the dwarf galaxies that appear too large and those of GCs that are too small. The evolution of the SRs up to z = 4 permits to reveal the complex evolutionary paths of galaxies in the SRs and indicate that the line marking the zone of exclusion, visible in the log(⟨I⟩e)−​log(Re) and the log(Re)−​log(M*) planes, is the trend followed by virialized and passively evolving systems. Conclusions. We speculate that the observed SRs originate from the intersection of the virial theorem and a relation L = L0′σβ where the luminosities depend on the star formation history.

On the [α/Fe]–[Fe/H] relations in early-type galaxies

Abstract We study how the predicted [α/Fe]–[Fe/H] relations in early-type galaxies vary as functions of their stellar masses, ages, and stellar velocity dispersions, by making use of cosmological chemodynamical simulations with feedback from active galactic nuclei. Our model includes a detailed treatment for the chemical enrichment from dying stars, core-collapse supernovae (both Type II and hypernovae) and Type Ia supernovae. At redshift $z$ = 0, we create a catalogue of 526 galaxies, among which we determine 80 early-type galaxies. From the analysis of our simulations, we find [α/Fe]–[Fe/H] relations similar to the Galactic bulge. We also find that, in the oldest galaxies, Type Ia supernovae start to contribute at higher [Fe/H] than in the youngest ones. On the average, early-type galaxies with larger stellar masses (and, equivalently, higher stellar velocity dispersions) have higher [α/Fe] ratios, at fixed [Fe/H]. This is qualitatively consistent with the recent observations of Sybilska et al., but quantitatively there are mismatches, which might require stronger feedback, sub-classes of Type Ia Supernovae, or a variable initial mass function to address.

DISKY ELLIPTICAL GALAXIES AND THE ALLEGEDLY OVER-MASSIVE BLACK HOLE IN THE COMPACT MASSIVE “ES” GALAXY NGC 1271

ABSTRACT While spiral and lenticular galaxies have large-scale disks extending beyond their bulges, and most local early-type galaxies with 1010 < M */M ⊙ < 2 × 1011 contain a disk (e.g., ATLAS3D), the early-type galaxies do possess a range of disk sizes. The edge-on, intermediate-scale disk in the “disky elliptical” galaxy NGC 1271 has led to some uncertainty regarding its spheroidal component. Walsh et al. reported a directly measured black hole mass of for this galaxy, which they remarked was an order of magnitude greater than what they expected based on their derivation of the host spheroid’s luminosity. Our near-infrared image analysis supports a small embedded disk within a massive spheroidal component with (using from Walsh et al.). This places NGC 1271 just 1.6σ above the near-linear M bh–M sph,* relation for early-type galaxies. Therefore, past speculation that there may be a systematic difference in the black hole scaling relations between compact massive early-type galaxies with intermediate-scale disks, i.e., ES galaxies such as NGC 1271, and early-type galaxies with either no substantial disk (E) or a large-scale disk (S0) is not strongly supported by NGC 1271. We additionally (1) show how ES galaxies fit naturally in the (“bulge”-to-total)-(morphological-type) diagram, while noting a complication with recent revisions to the Hubble-Jeans tuning-fork diagram, (2) caution about claims of over-massive black holes in other ES galaxies if incorrectly modeled as S0 galaxies, and (3) reveal that the compact massive spheroid in NGC 1271 has properties similar to bright bulges in other galaxies, which have grown larger-scale disks.

X-RAY SCALING RELATION IN EARLY-TYPE GALAXIES: DARK MATTER AS A PRIMARY FACTOR IN RETAINING HOT GAS

We have revisited the X-ray scaling relations of early type galaxies (ETG) by investigating, for the first time, the LX,Gas - MTotal relation in a sample of 14 ETGs. In contrast to the large scatter (by a factor of 102-103) in the LX,Total - LB relation, we found a tight correlation between these physically motivated quantities with a rms deviation of a factor of 3 in LX,Gas = 1038 - 1043 erg s-1 or MTotal = a few x 1010 - a few x 1012 Mo. More striking, this relation becomes even tighter with a rms deviation of a factor of 1.3 among the gas-rich galaxies (with LX,Gas > 1040 erg s-1). In a simple power-law form, the new relation is (LX,Gas / 1040 erg s-1) = (MTotal / 3.2 x 1011 Mo)3. This relation is also consistent with the steep relation between the gas luminosity and temperature, LX,Gas ~ TGas4.5, identified by Boroson, Kim & Fabbiano (2011), if the gas is virialized. Our results indicate that the total mass of an ETG is the primary factor in regulating the amount of hot gas. Among the gas-poor galaxies (with LX,Gas < a few x 1039 erg s-1), the scatter in the LX,Gas - MTotal (and LX,Gas - TGas) relation increases, suggesting that secondary factors (e.g., rotation, flattening, star formation history, cold gas etc.) may become important.

The SAURON project - XVIII. The integrated UV-line-strength relations of early-type galaxies

Using far (FUV) and near (NUV) ultraviolet photometry from guest investigator programmes on the Galaxy Evolution Explorer (GALEX) satellite, optical photometry from the MDM Observatory and optical integral-field spectroscopy from SAURON, we explore the UV-linestrength relations of the 48 nearby early-type galaxies in the SAURON sample. Identical apertures are used for all quantities, avoiding aperture mismatch. We show that galaxies with purely old stellar populations show well-defined correlations of the integrated FUV-V and FUV-NUV colours with the integrated Mgb and Hbeta absorption linestrength indices, strongest for FUV-NUV. Correlations with the NUV-V colour, Fe5015 index and stellar velocity dispersion are much weaker. These correlations put stringent constraints on the origin of the UV-upturn phenomenon in early-type galaxies, and highlight its dependence on age and metallicity. In particular, despite recent debate, we recover the negative correlation between FUV-V colour and Mg linestrength originally publicised by Burstein et al. (1988), which we refer to as the "Burstein relation", suggesting a positive dependence of the UV-upturn on metallicity. We argue that the scatter in the correlations is real, and present mild evidence that a strong UV excess is preferentially present in slow-rotating galaxies. We also demonstrate that most outliers in the correlations are galaxies with current or recent star formation, some at very low levels. We believe that this sensitivity to weak star formation, afforded by the deep and varied data available for the SAURON sample, explains why our results are occasionally at odds with other recent but shallower surveys. This is supported by the analysis of a large, carefully-crafted sample of more distant early-type galaxies from the Sloan Digital Sky Survey (SDSS), more easily comparable with current and future large surveys.

Studying the diverse nature of faint galaxies in nearby clusters of the WINGS sample

AbstractWe present the first results of our X‐shooter observations for a sample of dwarf (–17 &lt; MB &lt; –15) galaxies in nearby (0.04 &lt; z &lt; 0.07) galaxy clusters. This luminosity range is fundamental to trace the evolution of higher‐z star‐forming cluster galaxies down to the present day, and to explore the galaxy scaling relations of early‐type galaxies over a broad mass range. Thanks to high resolution and availability of several lines we can derive the velocity dispersion of the galaxies in this range of luminosities and we begin the construction of the fundamental plane of faint early‐type galaxies (© 2011 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

Scaling relations in early-type galaxies from integral-field stellar kinematics

Early-type galaxies (ETGs) satisfy a now classic scaling relation Re ∝ σ1.2eI−0.8e, the Fundamental Plane (FP; Djorgovski &amp; Davis 1987; Dressler et al. 1987), between their size, stellar velocity dispersion and mean surface brightness. A significant effort has been devoted in the past twenty years to try to understand why the coefficients of the relation are not the ones predicted by the virial theorem Re ∝ σ2eI−1e.

The Hot Gas Halos of Galaxies in Groups

We use Chandra observations of 13 nearby groups of galaxies to investigate the hot gas content of their member galaxies. We find that a large fraction of near-IR bright, early-type galaxies in groups have extended X-ray emission, indicating that they retain significant hot gas halos even in these dense environments. In particular, we detect hot gas halos in ~80% of L_K > L_star galaxies. We do not find a significant difference in the L_K-L_X relation for detected group and cluster early-type galaxies. However, we detect X-ray emission from a significantly higher fraction of galaxies brighter than L_star in groups compared to clusters, indicating that a larger fraction of galaxies in clusters experience significant stripping of their hot gas. In addition, group and cluster galaxies appear to be X-ray faint compared to field galaxies, though a Chandra based field sample is needed to confirm this result. The near-IR bright late-types galaxies in clusters and groups appear to follow the L_K-L_X relation for early-type galaxies, while near-IR fainter late-type galaxies are significantly more X-ray luminous than this relation likely due to star formation. Finally, we find individual examples of ongoing gas stripping of group galaxies. One galaxy shows a 40-50 kpc X-ray tail, and two merging galaxy systems show tidal bridges/tails of X-ray emission. Therefore, stripping of hot galactic gas through both ram pressure and tidal forces does occur in groups and clusters, but the frequency or efficiency of such events must be moderate enough to allow hot gas halos in a large fraction of bright galaxies to survive even in group and cluster cores.

How young stellar populations affect the ages and metallicities of galaxies

Context. Two important stellar-population parameters (age and metallicity) of the dominant stellar populations (DSPs) of galaxies are usually estimated by comparing the observed absorption line indices or colors to predictions of some simple stellar population models. However, some studies show that there is actually recent star formation in galaxies, including early type ones. This suggests that we may not be obtaining accurate the two stellar-population parameters for the DSPs of galaxies. This is obvious when we estimate the two parameters by colors, because the youngest populations dominate the light and make the fitted stellar populations younger and richer in metal. Aims. We plan to study how young populations (YSPs) in composite stellar populations (CSPs) affect the colors of star systems and to analyze how the stellar ages and metallicities derived from colors possibly deviate from those of the DSPs. Methods. The techniques of stellar population synthesis and Monte Carlo process are used in this analysis. Results. It is found that the age and mass fraction of a YSP affect colors of a mixed star system significantly, but the former is stronger. In addition, our results show that the stellar ages and metallicities derived directly from a pair of colors are about 2.14 Gyr younger, while 0.0027 more metal rich on average than those of the DSPs of composite stellar systems. Some possible distributions of the differences between stellar-population parameters determined by colors and those of DSPs of CSPs are presented. The possible distributions of the differences between colors of CSPs and those of their DSPs are also shown. Stellar ages and metallicities measured by colors and line-strength indices are compared in the work, with a sample of 18 galaxies. Furthermore, the YSPs may affect the fundamental plane and Kormendy relation of early type galaxies.

The impact of high pressure cluster environment on the X-ray luminosity of Coma early-type galaxies

We present an observational study of the LX vs. relation for early-type galaxies in the Coma cluster based on the XMM-Newton survey data. Compared to a similar relation for a sample dominated by field early-type galaxies, the Coma cluster galaxies show a flatter slope. Our calculations show that adiabatic compression produces a flattening in the LX vs. relation that is in remarkable agreement with the observed effect. Our scenario is further supported by the observed compactness of the X-ray emission of Coma galaxies.

Scaling relations in early-type galaxies belonging to groups

We present a photometric analysis of a large sample of early-type galaxies in 16 nearby groups, imaged with the Wide-Field Camera on the Isaac Newton Telescope. Using a two-dimensional surface brightness decomposition routine, we fit Sersic (r1/n) and exponential models to their bulge and disc components, respectively. Dividing the galaxies into three subsamples according to the X-ray luminosities of their parent groups, we compare their photometric properties. Galaxies in X-ray luminous groups tend to be larger and more luminous than those in groups with undetected or low X-ray luminosities, but no significant differences in n are seen. Both normal and dwarf elliptical galaxies in the central regions of groups are found to have cuspier profiles than their counterparts in group outskirts. Structural differences between dwarf and normal elliptical galaxies are apparent in terms of an offset between their ‘photometric planes’ in the space of n, re and μ0. Dwarf ellipticals are found to populate a surface, with remarkably low scatter, in this space with significant curvature, somewhat similar to the surfaces of constant entropy proposed by Marquez et al. Normal ellipticals are offset from this distribution in a direction of higher specific entropy. This may indicate that the two populations are distinguished by the action of galaxy merging on larger galaxies.

A catalogue and analysis of X-ray luminosities of early-type galaxies

We present a catalogue of X-ray luminosities for 401 early-type galaxies, of which 136 are based on newly analysed ROSAT PSPC pointed observations. The remaining luminosities are taken from the literature and converted to a common energy band, spectral model and distance scale. Using this sample we fit the LX: LB relation for early-type galaxies and find a best-fit slope for the catalogue of ∼2.2. We demonstrate the influence of group-dominant galaxies on the fit and present evidence that the relation is not well modelled by a single power-law fit. We also derive estimates of the contribution to galaxy X-ray luminosities from discrete-sources and conclude that they provide . We compare this result with luminosities from our catalogue. Lastly, we examine the influence of environment on galaxy X-ray luminosity and on the form of the relation. We conclude that although environment undoubtedly affects the X-ray properties of individual galaxies, particularly those in the centres of groups and clusters, it does not change the nature of whole populations.

Internal Color Gradients and the Color-Magnitude Relation of Early-Type Galaxies

The traditional use of fixed apertures in determining the well-known color-magnitude (CM) relation of early-type galaxies, coupled with the presence of radial color gradients within these systems, introduces a bias in the CM relation itself. The effect of this bias is studied here, deriving a CM relation that is based on color measurements carried out homogeneously within an aperture of radius equal to that of the galaxy effective radius. A sample of 48 giant early-type galaxies in the Coma Cluster, with CCD observations in the U and V band, is used for this derivation. It is found that internal radial color gradients in early-type galaxies cannot be neglected when discussing the colors of these systems, and that the CM relation derived using color measurements within the effective radius is significantly flatter than those based on fixed-aperture color measurements. With the currently available data, it is impossible to determine whether the relation is completely flat, or whether a small correlation is still present between galaxy color and luminosity.

Hubble Space TelescopePhotometry and Keck Spectroscopy of the Rich Cluster MS 1054−03: Morphologies, Butcher‐Oemler Effect, and the Color‐Magnitude Relation atz= 0.83

We present a study of 81 I-band selected, spectroscopically confirmed members of the X-ray cluster MS 1054-03 at z = 0.83. Redshifts and spectral types were determined from Keck spectroscopy. Morphologies and accurate colors were determined from a large mosaic of HST WFPC2 images in RF606W and IF814W, corresponding to U and B in the rest frame. Early-type galaxies constitute only 44% of this galaxy population. This fraction is much lower than in comparable rich clusters at low redshift. Thirty-nine percent are spiral galaxies, and 17% are mergers. The early-type galaxies follow a tight and well-defined color-magnitude relation, with the exception of a few outliers. The observed scatter is 0.029 ± 0.005 mag in rest frame U-B. Most of the mergers lie close to the CM relation defined by the early-type galaxies. They are bluer by only 0.07 ± 0.02 mag, and the scatter in their colors is 0.07 ± 0.04 mag. Spiral galaxies in MS 1054-03 exhibit a large range in their colors. The bluest spiral galaxies are ~0.7 mag bluer than the early-type galaxies, but the majority is within ±0.2 mag of the early-type galaxy sequence. The red colors of the mergers and the majority of the spiral galaxies are reflected in the fairly low Butcher-Oemler blue fraction of MS 1054-03: fB = 0.22 ± 0.05, similar to intermediate redshift clusters and much lower than previously reported values for clusters at z ~ 0.8. The slope and scatter of the CM relation of early-type galaxies are roughly constant with redshift, confirming previous studies that were based on ground-based color measurements and very limited membership information. However, the scatter in the combined sample of early-type galaxies and mergers (i.e., the sample of future early-type galaxies) is twice as high as the scatter of the early-type galaxies alone. This is a direct demonstration of the progenitor bias: high-redshift early-type galaxies seem to form a homogeneous, old population because the progenitors of the youngest present-day early-type galaxies are not included in the sample.

Near‐infrared Imaging of Early‐Type Galaxies. II. Global Photometric Parameters

An imaging survey of 341 nearby early-type galaxies in the near-infrared K-band atmospheric window (2.2 μm) is described. The galaxies primarily reside in 13 nearby rich clusters (85%), while some additional galaxies are drawn from loose groups (12%) and the general field (3%). Surface photometry was measured for the entire sample. Detailed corrections were derived from an extensive grid of seeing-convolved r1/4 models and then applied to the isophotal surface brightness, aperture magnitude, and ellipticity profiles. Global photometric parameters were derived from this seeing-corrected photometry. More than 25% of the sample has been observed at least twice, and these repeat measurements demonstrate the small internal uncertainties on the derived global photometric parameters. Extensive comparisons with aperture photometry from the literature demonstrate that the photometric system is fully consistent with other photometric systems to ≤0.01 mag and confirm the estimates of internal random uncertainties. Additional global parameters are drawn from the literature in a homogeneous manner in order to construct a large catalog of galaxy properties: 95% of the galaxies have a velocity dispersion, 69% have a Mg2 index, 80% have an optical reff and μeff, 82% have a Dn, and 81% have a derived optical - infrared color measurement. This large data set provides excellent source material for investigations of the physical origins of the global scaling relations of early-type galaxies, velocity fields in the local universe, and comparisons to higher redshift early-type galaxies.

Fundamental Plane and Merger Scenario

The Fundamental Plane (FP) is one of the most important universal relations in early type galaxies because it contains valuable information about the formative and evolutionary process of galaxies (Djorgovski &amp; Davis 1987, Dressler et al. 1987). The commonly used form of the scaling relation in the FP is described as Re = σAIB, where Re, σ, and I are effective radius, central velocity dispersion, and mean surface brightness of elliptical galaxies, respectively. The exponents A, B are considered to be 1.56 ± 0.07 and −0.94 ± 0.09 in the FP derived by K band photometry, respectively, and these values deviate significantly from the values A = 2.0 and B = −1.0 expected from virial theorem (Pahre et al. 1995; Djorgovski, Pahre, &amp; de Carvalho 1996). This apparent deviation requires that the ratio of dynamical mass (M) to luminosity of elliptical galaxies (L) depends on M as M/L ∝ Mα (α = 0.12 ± 0.03 for K band). Possible interpretations for the required dependence of M/L on M are generally considered to be divided into the following two. One is that the required dependence of M/L on M results from the fact that the mean stellar age and metalicity of elliptical galaxies depend systematically on M. The other is that the required dependence reflects the M dependence of structural and kinematical properties of elliptical galaxies (“nonhomology”). Although we should not neglect the importance of stellar populations in generating the M dependence of the M/L (Renzini &amp; Ciotti 1993), we here consider that the origin of the required M dependence of M/L is closely associated with the structural and kinematical properties dependent on M or L in elliptical galaxies.

ROSAT observations of compact groups of galaxies

We have systematically analyzed a sample of 13 new and archival ROSAT PSPC observations of compact groups of galaxies: 12 Hickson Compact Groups plus the NCG 2300 group. We find that approximately two-thirds of the groups have extended X-ray emission and, in four of these, the emission is resolved into diffuse emission from gas at a temperature of $k$T $\sim 1$ keV in the group potential. All but one of the groups with extended emission have a spiral fraction of less than 50\%. The baryon fraction of groups with diffuse emission is 5--19\%, similar to the values in clusters of galaxies. However, with a single exception (HCG 62), the gas-to-stellar-mass ratio in our groups has a median value near 5\%, somewhat greater than the values for individual early-type galaxies and two orders of magnitude lower than in clusters of galaxies. The X-ray luminosities of individual group galaxies are comparable to those of similar field galaxies, although the L$_X$-L$_B$ relation for early-type galaxies may be flatter in compact groups than in the field.

THE INFRARED COLOR-MAGNITUDE RELATION FOR EARLY-TYPE GALAXIES IN THE PEGASUS I CLUSTER.

ABSTRACT Infrared and visual photometric data are presented for elliptical and S0 galaxies in the Pegasus I cluster of galaxies. Multiaperture measurements were made in the UBV and infrared by a 1.3-m telescope, and color indices and magnitudes were calculated in order to obtain a color-magnitude diagram. The well known correlation between galactic luminosity and redness is apparent in the diagram, with but two galaxies deviating significantly from the relation established. A two-color (U-V), (V-K) diagram of the Pegasus galaxies is also presented and compared with those of the Virgo and Coma clusters. Results averaged from the (K, (U-K)) and (V, (U-V)) color diagrams obtained are noted to indicate a distance modulus for the Pegasus cluster relative to the Virgo cluster of 2.32 + or - 0.37 m, consistent with a large deceleration of galaxies in the Local Supercluster.