The Redshift-Distance Relation. VIL Absolute Magnitudes of the First Three Ranked Cluster Galaxies as Functions of Cluster Richness and Bautz-Morgan Cluster Type: the Effect of q_{o}

1973 ◽  
Vol 183 ◽  
pp. 743 ◽  
Author(s):  
Allan Sandage ◽  
Eduardo Hardy
Keyword(s):  
Cluster Galaxies ◽  
Cluster Type ◽  
Absolute Magnitudes ◽  
Distance Relation

scholarly journals The K-Band Hubble Diagram for the Brightest Cluster Galaxies: A Test of Galaxy Formation Models

1999 ◽  
Vol 186 ◽  
pp. 407-407
Author(s):  
A. Aragón-Salamanca ◽  
C.M. Baugh ◽  
G. Kauffmann
Keyword(s):  
Galaxy Formation ◽  
Stellar Mass ◽  
Hubble Diagram ◽  
Redshift Range ◽  
Cluster Galaxies ◽  
Brightest Cluster Galaxies ◽  
Galaxy Formation And Evolution ◽  
Absolute Magnitudes ◽  
Luminosity Evolution ◽  
K Band

We analyze the K-band Hubble diagram for a sample of brightest cluster galaxies (BCGs) in the redshift range 0 < z < 1. We confirm that the scatter in the absolute magnitudes of the galaxies is small (0.3 magnitudes). The BCGs exhibit very little luminosity evolution in this redshift range: if q0 = 0.0 we detect no luminosity evolution; for q0 = 0.5 we measure a small negative evolution (i.e., BCGs were about 0.5 magnitudes fainter at z = 1 than today). If the mass in stars of these galaxies had remained constant over this period of time, substantial positive luminosity evolution would be expected: BCGs should have been brighter in the past since their stars were younger. A likely explanation for the observed zero or negative evolution is that the stellar mass of the BCGs has been assembled over time through merging and accretion, as expected in hierarchical models of galaxy formation. The colour evolution of the BCGs is consistent with that of an old stellar population (zform > 2) that is evolving passively. We can thus use evolutionary population synthesis models to estimate the rate of growth in stellar mass for these systems. We find that the stellar mass in a typical BCG has grown by a factor ≃ 2 since z ≃ 1 if q0 = 0.0 or by factor ≃ 4 if q0 = 0.5. These results are in remarkably good agreement with the predictions of semi-analytic models of galaxy formation and evolution set in the context of a hierarchical scenario for structure formation.

scholarly journals A New Look at Poor Groups of Galaxies

1999 ◽  
Vol 192 ◽  
pp. 433-439 ◽  
Author(s):  
Ann I. Zabludoff
Keyword(s):  
Dominant Role ◽  
Early Type ◽  
Equal Frequency ◽  
Galaxy Interactions ◽  
X Ray ◽  
Groups Of Galaxies ◽  
Cluster Galaxies ◽  
Group Members ◽  
Absolute Magnitudes ◽  
Star Formation Histories

We use a new fiber spectroscopic survey of 12 nearby, poor groups of galaxies to examine the dynamics and evolution of galaxies in these common, but poorly studied, environments. Some of our conclusions are: (1) The nine groups in our sample with diffuse X-ray emission are in fact bound systems with at least 20-50 group members with absolute magnitudes as faint as MB ~ −14 + 5 log10h. (2) Galaxies in each X-ray-detected group have not all merged together because a significant fraction of the group mass lies outside of the galaxies and in a common halo, thereby reducing the rate of galaxy-galaxy interactions. (3) The similarity of the recent star formation histories and the fraction of early type galaxies in some poor groups to those in rich clusters suggest that cluster-specific environmental effects may not play a dominant role in the recent evolution of cluster galaxies. The evolution of group and cluster members may be driven instead by galaxy-galaxy interactions, which are likely to occur with equal frequency in field groups and in groups that have recently fallen into clusters (i.e., subclusters).

МОДУЛЬНОЕ ПРОЕКТИРОВАНИЕ ВАКУУМНЫХ УСТАНОВОК ДЛЯ МИКРОЭЛЕКТРОННЫХ ТЕХНОЛОГИЙ

2020 ◽  
Vol 96 (3s) ◽  
pp. 489-493
Author(s):  
М.Г. Бирюков ◽  
В.В. Одиноков ◽  
В.В. Панин ◽  
В.М. Долгополов ◽  
А.В. Шубников
Keyword(s):  
Plasma Etching ◽  
Vacuum Plasma ◽  
Loading And Unloading ◽  
Cluster Type

Представлен модульный принцип создания вакуумно-плазменного оборудования для микроэлектронных технологий с использованием различных вариантов загрузки-выгрузки пластин в рабочий модуль (реактор): установки с поштучной ручной загрузкой-выгрузкой пластин, с поштучной загрузкой-выгрузкой пластин из шлюзовой камеры манипулятором, с поштучной загрузкой-выгрузкой пластин манипулятором из кассеты в кассету в шлюзовой камере, а также оборудование кластерного типа. Рабочие модули установок обеспечивают высокие требования к процессам плазмохимического травления. The paper presents modular principle of creating vacuum-plasma equipment for microelectronic technologies by using various options for loading and unloading wafers into a working module (reactor): systems with single manual loading and unloading wafers, with single loading and unloading wafers from a loadlock by a manipulator, with single loading and unloading wafers with a manipulator from a cassette-to-cassette in a loadlock, as well as cluster type equipment. Working modules of systems provide high requirements to the processes of plasma etching.

Coupled-pair theories and Davidson-type corrections for quasidegenerate states: The H4 model revisited

1988 ◽  
Vol 53 (9) ◽  
pp. 1919-1942 ◽  
Author(s):  
Josef Paldus ◽  
Paul E. S. Wormer ◽  
Marc Benard
Keyword(s):  
Electron Correlation ◽  
Model System ◽  
Coupled Cluster ◽  
Electron Model ◽  
Hydrogen Molecules ◽  
Double Zeta ◽  
Correlation Problem ◽  
Variational Approaches ◽  
Cluster Type ◽  
The Many

The performance of various variational and non-variational approaches to the many-electron correlation problem is examined for a simple four-electron model system consisting of two stretched hydrogen molecules in trapezoidal, rectangular and linear configurations, in which the degree of quasi-degeneracy can be continuously varied from a non-degenerate to an almost degenerate situation. In contrast to an earlier work (K. Jankowski and J. Paldus, Int. J. Quantum Chem. 18, 1243 (1980)) we employ a double-zeta plus polarization basis and examine both single reference and multireference configuration interaction and coupled-cluster-type approaches. The performance of various Davidson-type corrections is also investigated.

scholarly journals Observed Relations Between Physical Properties and MK Classification as Functions of Metal Abundance for F5-K4 Stars

1976 ◽  
Vol 72 ◽  
pp. 75-78
Author(s):  
M. Grenon
Keyword(s):  
Physical Properties ◽  
Spectral Range ◽  
Spectral Type ◽  
Photometric System ◽  
Luminosity Class ◽  
Empirical Relations ◽  
Metal Abundance ◽  
Systematic Effects ◽  
The Absolute ◽  
Absolute Magnitudes

The Geneva photometric system has been calibrated in terms of [M/H], θeff, Mv in the spectral range F5 to K4. As the spectral type is a datum generally available, we derive empirical relations showing the coupling of θeff and [M/H] at given spectral type and luminosity class. Similar relations are offered for the absolute magnitudes and provide a more accurate means for deriving spectroscopic parallaxes. Systematic effects on the estimation of the luminosity class are also shown.

scholarly journals Brightest cluster galaxies: the centre can(not?) hold

2020 ◽  
Vol 500 (1) ◽  
pp. 310-318
Author(s):  
Roberto De Propris ◽  
Michael J West ◽  
Felipe Andrade-Santos ◽  
Cinthia Ragone-Figueroa ◽  
Elena Rasia ◽  
...  
Keyword(s):  
Dark Matter ◽  
Local Environment ◽  
Major Axis ◽  
Theoretical Models ◽  
Dark Matter Halo ◽  
Gas Distribution ◽  
X Ray ◽  
Cluster Galaxies ◽  
Peculiar Velocities ◽  
Brightest Cluster Galaxies

ABSTRACT We explore the persistence of the alignment of brightest cluster galaxies (BCGs) with their local environment. We find that a significant fraction of BCGs do not coincide with the centroid of the X-ray gas distribution and/or show peculiar velocities (they are not at rest with respect to the cluster mean). Despite this, we find that BCGs are generally aligned with the cluster mass distribution even when they have significant offsets from the X-ray centre and significant peculiar velocities. The large offsets are not consistent with simple theoretical models. To account for these observations BCGs must undergo mergers preferentially along their major axis, the main infall direction. Such BCGs may be oscillating within the cluster potential after having been displaced by mergers or collisions, or the dark matter halo itself may not yet be relaxed.

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