First-ranked Cluster Galaxies Research Articles

The Tolman Surface Brightness Test for the Reality of the Expansion. I. Calibration of the Necessary Local Parameters

Surface brightness averages are calculated at various metric radii in each galaxy in the sample. The definition of such radii by Petrosian uses ratios of observed surface photometric data. Petrosian radii have important properties for the Tolman test which are reviewed in this paper. The observed surface brightnesses are listed for 118 first-ranked cluster galaxies at Petrosian η radii of 1.0, 1.3, 1.5, 1.7, 2.0, and 2.5 mag. The three local diagnostic correlation diagrams are defined and discussed. We review the Tolman test and show that, although recipes from the standard cosmological model that already have the Tolman signal incorporated are required to calculate linear radii and absolute magnitudes from the observed data, the test is nevertheless free from the hermeneutical circularity dilemma occasionally claimed in the literature. The reasons are the observed mean surface brightness (1) is independent of any assumptions of cosmological model, (2) does not depend on the existence of a Tolman signal because it is calculated directly from the data using only angular radii and apparent magnitudes, and (3) can be used to search for the Tolman signal because it carries the bulk of that signal.

Is the velocity-distance relation for galaxies linear?

Diameters of ScI galaxies, the luminosities of supernovae of type Ia at maximum light, and the brightness of central galaxies in rich clusters are examined as potential yardsticks or standard candles for study of the velocity-distance relationship. Both supergiant ScI galaxies and supernovae Ia (which have luminosities that differ by up to a factor of approximately 10) are found to be unsuitable for such a study. The remarkably small luminosity dispersion of first-ranked cluster galaxies (which is not yet understood physically) suggests that deviations from a linear velocity-distance relationship are less, approximately 20% out to red shifts of approximately 40,000 km.s-1.

Steps toward the Hubble constant. IX - The cosmic value of H(0) freed from all local velocity anomalies

view Abstract Citations (123) References (133) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Steps toward the Hubble Constant. IX. The Cosmic Value of H 0 Freed from All Local Velocity Anomalies Sandage, Allan ; Tammann, G. A. Abstract The velocity which the Virgo Cluster would have if it were freed from all local anomalies relative to the cosmological Machian frame is determined by bringing the remote velocity frame to the Virgo Cluster distance. Three independent methods are used to accomplish this: (1) distances of 17 "remote" clusters are determined relative to Virgo by a number of independent methods; the equation of the Hubble diagram correlation that relates redshift and the distance modulus difference from Virgo is then read for its velocity value at the modulus difference of {DELTA}(m-M) = 0.00; (2) a similar calculation is made using apparent magnitudes of first-ranked cluster galaxies in relatively distant clusters, and (3) the same calculation is made using distant supernovae of Type Ia. The resulting velocity of Virgo, called the "cosmic expansion velocity freed from local velocity anomalies" is v_cosmic_(Virgo) = 1144 +/- 18 km s^-1^. The distance to the Virgo Cluster core is determined from six independent methods using recent data, giving (m-M) = 31.70 +/- 0.09, or D = 21.9 +/- 0.9 Mpc. Combining the cosmic Virgo velocity with this distance, which now is of unprecedented accuracy, gives the Hubble constant to be H_0_ = 52 +/- 2 km s^-1^ Mpc^-1^. If a still more accurate distance D (in Mpc) to the Virgo Cluster core becomes available, the calculated Hubble constant will be changed to H_0_ = 52(21.9/D) km s^-1^ Mpc^-1^. As a by-product (but which does not enter the method devised here to find H_0_), we determine the infall velocity of the Local Group toward Virgo (the retarded expansion effect) to be 168 +/- 50 km s^-1^. A firm lower limit to H_0_ can be obtained by putting this infall velocity to zero so that v(Virgo)_cosmic_ = v(Virgo)_observed_ = 976 +/- 45 km s^-1^. For this limiting case (which is physically unreal unless the Virgo pull is zero, and therefore {DELTA} = 0) the lower limit to the global value of H_0_ becomes H_0(min)_ = (45 +/- 3)(21.9/D) km s^-1^ Mpc^-1^. Publication: The Astrophysical Journal Pub Date: December 1990 DOI: 10.1086/169453 Bibcode: 1990ApJ...365....1S Keywords: Cosmology; Hubble Constant; Virgo Galactic Cluster; Andromeda Galaxy; Interstellar Matter; Local Group (Astronomy); Planetary Nebulae; Red Shift; Spatial Distribution; Astrophysics; COSMOLOGY; GALAXIES: CLUSTERING; GALAXIES: DISTANCES; GALAXIES: REDSHIFTS full text sources ADS | data products SIMBAD (19) NED (17) Related Materials (9) Part 1: 1974ApJ...190..525S Part 2: 1974ApJ...191..603S Part 3: 1974ApJ...194..223S Part 4: 1974ApJ...194..559S Part 5: 1975ApJ...196..313S Part 6: 1975ApJ...197..265S Part 7: 1976ApJ...210....7S Part 8: 1982ApJ...256..339S Part 10: 1995ApJ...446....1S

First-ranked cluster galaxies - A two-population model

view Abstract Citations (25) References (14) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS First-ranked Cluster Galaxies: A Two-Population Model Bhavsar, Suketu P. Abstract The small dispersion in the absolute magnitudes (~ 0.35 mag) of first-ranked galaxies in rich clusters has been the cause for much debate between the "special" and "statistical" hypotheses for these galaxies. We present statistical evidence that it is not the one or the other but a combination. The distribution in magnitudes of the brightest galaxies is best explained if they consist of two distinct populations of objects; a population of special galaxies having a Gaussian distribution of magnitudes with a small dispersion (0.21 mag), and a population of extremes of a statistical luminosity function. The best fit model requires that 63% of the clusters have a special galaxy that is, on average, 0.48 mag brighter than the brightest normal galaxy. The model also requires the luminosity function of galaxies in clusters to be much steeper at the very tail end than conventionally described. Publication: The Astrophysical Journal Pub Date: March 1989 DOI: 10.1086/167229 Bibcode: 1989ApJ...338..718B Keywords: Astronomical Photometry; Computational Astrophysics; Galactic Clusters; Astronomical Models; Brightness Distribution; Electrophotometers; Astrophysics; GALAXIES: CLUSTERING; GALAXIES: PHOTOMETRY; LUMINOSITY FUNCTION full text sources ADS |

21 centimeter line width distances of cluster galaxies and the value of H0

Locally calibrated blue and infrared Tully-Fisher (TF) relations are applied to an essentially (i.e., 82%) complete sample of 81 Sab-Sm galaxies which are bona fide members of the Virgo Cluster. Because of the proximate completeness of the sample a nearly unbiased Virgo modulus of (m - M)^0^ = 31.60 + 0.15 can be derived. The result is in perfect agreement with independent recent determinations which gives additional justification to the adopted local calibrators. The distance modulus from the blue TF relation carries higher weight because infrared H magnitudes are available for only 25 Virgo members. The remaining H magnitudes are derived from a well defined (B-H)/log {DELTA}v_21_ relation; nevertheless, the 25 members suffice to show that the bTF and iTF relations give almost identical distance moduli from any selected Virgo subsample. The intrinsic scatter about the two TF relations is σ_M_ = 0.7 mag. This is considerably larger than the observed scatter in the UMa Cluster and in 10 more distant clusters for which B and H magnitudes and 21 cm line widths are available; their reduced scatter discloses that the hitherto investigated samples merely contain the brightest spirals at any given line width. Distance determinations of these clusters can therefore only be achieved by fitting the upper envelopes of their TF relations onto the blue and infrared upper envelopes of the Virgo Cluster. The resulting distances define a linear expansion law with a small scatter. The linearity of the expansion can be extended for the range from v ~ 200 km s^-1^ out to v ~ 20,000 km s^-1^ using external data. The present cluster data require a Hubble constant of H_0_ = 56.6 +/- 0.9 km s^-1^ Mpc^-1^ which implies through first-ranked cluster galaxies 51 < H_0_(global) < 56 at very large distances; the external error of these values is probably less than 20%. A search for Local Group motion toward the microwave background dipole remains inconclusive.

Alignment statistics of clusters with their brightest members at bright and faint isophotes

For a sample of 21 first-ranked cluster galaxies with published isophotal photometry and position angles of these isophotes, it is found that the major axes of both the bright and faint isophotal contours tend to be aligned within about 30 deg of the major axis of the parent cluster. This supports the hypothesis that first-ranked galaxies are formed already aligned with their parent clusters rather than the hypothesis that only outer envelopes which accreted after formation are aligned with the cluster. 21 references.

The Cosmic Distance Scale

The zero-point of the extragalactic distance scale, defined by about two dozens of nearby, late-type galaxies, has remained nearly unchanged for the last decade, in spite of the advent of new techniques and great efforts. The distances are essentially tied to trigonometric parallax stars and hence independent of the Hyades modulus; they are consistent with RR Lyr stars. The mean zero-point is therefore probably secure to better than 10%.All known secondary distance indicators are still affected by zero-point errors, by problems in the definition of their relation between distance indicator and absolute magnitude (or linear size), and/or by selection bias. The effect of the very important selection bias (Malmquist effect), which causes a seemingly non-linear expansion field, is illustrated by two examples. To test for any true deviations from a linear expansion the Hubble diagram of nearly bias-free first-ranked cluster galaxies and supernovae Ia is shown; this imposes stringent limits on any non-linearity of the Hubble flow within v<5000 km s−1.After freeing the available distances of field galaxies from selection bias and after reducing them to a common zero-point, one finds HO=55–65. Several distance indicators require a best Virgo cluster modulus of (m-M)=31.60, which implies for the Coma cluster (m-M)=35.38 and, with v(Coma)=7217 km s−1, HO=60. Supernovae Ia and first-ranked cluster galaxies out to large distances give HO (global)=53. Thus the evidence from clusters and field galaxies is best satisfied by HO=55; the assigned mean error of ±7 is to indicate a 3σ range of 35<HO<75.Purely physical methods to determine extragalactic distances have modest weight yet; they will contribute eventually much to the determination of HO.If HO were as large as 100, several paradoxa would arise. The Milky Way would have a very high supernova frequency, our Galaxy and M31 would be oversized, the baryon density would fall short to bind clusters, and Friedman universes were excluded.Because all systematic errors have conspired and probably still conspire to measure HO too high, the true value could well be 40. Until new, decisive evidence becomes available, it is suggested for all practical purposes to use HO=50.

The Status of the Hubble Diagram In 1986

We present visual and near-infrared Hubble diagrams for first-ranked cluster galaxies, and moderate-flux and high-flux radio galaxies. The photometric improvements and the extension of the diagrams to large redshifts (up to z ≃ 1.8) for both 3CR and “1 Jy” class radio galaxies are highlighted. The absolute luminosities of these three types of “standard candles”, where their redshifts overlap, agree adequately. The near-IR (2μm) Hubble diagrams may be used to determine the global deceleration parameter, q0, and the current data favor q0 ∼ +0.2 to +0.3. The sensitivity to evolutionary changes in the giant galaxies is quite modest at these long wavelengths. On the other hand, the visual regime (BV R) shows a dramatic dependence on differential evolution effects, which dominate over the cosmological model differences. Most radio galaxies apparently have had active star formation, with a continually declining rate, but a few are quite faint and red; they may have had a relatively passive evolution.

Kinematic evidence of satellite galaxy populations in the potential wells of first-ranked cluster galaxies

The velocities of 38 centrally positioned galaxies (r much less than 100 kpc) were measured relative to the velocity of the first-ranked galaxy in 14 rich clusters. Analysis of the velocity distribution function of this sample and of previous data shows that the population cannot be fit by a single Gaussian. An adequate fit is obtained if 60 percent of the objects lie in a Gaussian with sigma = 250 km/s and the remainder in a population with sigma = 1400 km/s. All previous data sets are individually consistent with this conclusion. This suggests that there is a bound population of galaxies in the potential well of the central galaxy in addition to the normal population of the cluster core. This is taken as supporting evidence for the galactic cannibalism model of cD galaxy formation.

CCD observations of Abell clusters. IV - Surface photometry of 175 brightest cluster galaxies

view Abstract Citations (113) References (50) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS CCD Observations of Abell clusters. IV. Surface photometry of 175 brightest cluster galaxies. Hoessel, J. G. ; Schneider, D. P. Abstract The authors present a consistent body of CCD aperture photometry and surface photometry for the brightest galaxies in 175 clusters drawn from the Abell catalog. The data confirm earlier work showing that the dispersion in the aperture luminosities for first-ranked cluster galaxies is ≡0.32 mag, as well as the documented trends of luminosity with Bautz-Morgan class and cluster richness. Fits of Hubble and de Vaucouleurs models to the radial surface-brightness profiles verify the strong relationship between galaxy structure and absolute luminosity. The average core radius for the sample is 2.4 kpc, while the mean effective radius is 32 kpc. The structure parameter alpha, which ranges from 0.3 to 2.0, has a mean value of 0.75 when measured at the 16-kpc radius used as the standard aperture for the magnitudes. Half of these objects are multiple-nucleus systems. Publication: The Astronomical Journal Pub Date: September 1985 DOI: 10.1086/113871 Bibcode: 1985AJ.....90.1648H Keywords: Astronomical Photometry; Galactic Clusters; Luminosity; Charge Coupled Devices; Cosmology; Galactic Nuclei; Galactic Structure; Hubble Diagram; Red Shift; Astrophysics full text sources ADS | data products SIMBAD (179) NED (170) Related Materials (3) Part 1: 1983ApJ...264..337S Part 2: 1983ApJ...268..476S Part 4: 1991AJ....101.1561P

The structure of first-ranked cluster galaxies and the radius-magnitude relation

The structure of first-ranked cluster galaxies and the radius-magnitude relation

The nature of multiple-nucleus cluster galaxies

view Abstract Citations (34) References (19) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The nature of multiple-nucleus cluster galaxies Merritt, D. Abstract In models for the evolution of galaxy clusters which include dynamical friction with the dark binding matter, the distribution of galaxies becomes more concentrated to the cluster center with time. In a cluster like Coma, this evolution could increase by a factor of approximately 3 the probability of finding a galaxy very close to the cluster center, without decreasing the typical velocity of such a galaxy significantly below the cluster mean. Such an enhancement is roughly what is needed to explain the large number of first-ranked cluster galaxies which are observed to have extra 'nuclei'; it is also consistent with the high velocities typically measured for these 'nuclei'. Unlike the cannibalism model, this model predicts that the majority of multiple-nucleus systems are transient phenomena, and not galaxies in the process of merging. Publication: The Astrophysical Journal Pub Date: May 1984 DOI: 10.1086/184257 Bibcode: 1984ApJ...280L...5M Keywords: Galactic Clusters; Galactic Evolution; Galactic Nuclei; Astronomical Models; Luminosity; Orbital Elements; Astrophysics full text sources ADS |

Colors and magnitudes predicted for high redshift galaxies

Ultraviolet observations of nearby galaxies with the ANS are used to derive ultraviolet spectra for different galaxy types. These spectra are used with existing visible spectrophotometry to calculate K-corrections, and to predict colors and magnitudes for various galaxy types as a function of redshifts, to z = 2. No evolutionary effects are considered. It appears that the first-ranked cluster galaxies on blue emulsions should be spirals for z greater than or approximately equal to 0.5.

Properties of the cD galaxies in poor clusters

view Abstract Citations (41) References (27) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Properties of the cD galaxies in poor clusters. Schild, R. ; Davis, M. Abstract Aperture photometry and redshifts of cD galaxies in poor clusters are presented. In their B-V and V-R colors and in their absorption line spectra, the poor-cluster cD's are very like the rich-cluster cD's. However, the poor-cluster cD's are comparable in brightness to Sandage's first-ranked cluster galaxies, but not as bright as the cD's in rich clusters. Publication: The Astronomical Journal Pub Date: March 1979 DOI: 10.1086/112423 Bibcode: 1979AJ.....84..311S Keywords: Astronomical Photometry; Galactic Clusters; Galactic Structure; Red Shift; Luminosity; Optical Correction Procedure; Ubv Spectra; Visual Photometry; Astrophysics; Galaxies:Photometry; Galaxies:Redshifts full text sources ADS | data products NED (22)

Observations of a distant cluster of galaxies

Image-tube-dissector scans of the central galaxy in the faint cluster 1305+2952 over the wavelength range from 4000 to 7100 A are examined. The strongest and most prominent features are shown to be a step in the continuum at 5140 A and a very large (R-I) color index. A redshift of 0.947 is taken to be the most probable value that is consistent with the observations. It is concluded that if this redshift is correct, the central galaxy is much more luminous and much bluer than standard (local) first-ranked cluster galaxies.

The Redshift-Magnitude Relation for Radio Galaxies

We examine the Hubble diagram for radio galaxies and compare radio galaxies and first-ranked cluster galaxies as cosmological test objects. Radio source identification programs are now producing reliable identifications with galaxies as faint as V ≈ 23 and spectroscopy of these objects has already resulted in the discovery of galaxies with redshifts as high as 0.75, thus there are great expectations for progress in the near future. As in the past, indeterminate corrections, notably luminosity evolution and a possible correlation between radio power and optical luminosity, preclude the determination of qo.

Dynamical friction - The Hubble diagram as a cosmological test

Effects on the Hubble diagram of the frictional accretion of small cluster galaxies by large ones, to which Ostriker and Tremaine have recently drawn attention, must be accurately determined if the magnitude-redshift relation is to become a viable cosmological test. We find that the process might be detectable through the concomitant change in galaxy colors, but that its effect on the dispersion of magnitudes of first-ranked cluster galaxies would be negligible even if the change in average magnitude is very important. The sign of the effect of accretion on the luminosity observed within a given aperture depends on the structures of the galaxies involved. The size of the effect not only depends sensitively on the galaxy structures, but is also amplified when the relatively recent collapse times of the clusters are taken into account. It is vital to answer the complicated observational and theoretical questions raised by these preliminary calculations, because the Hubble diagram remains the most promising approach to the deceleration parameter q/sub 0/. Local tests of the density of the universe do not give equivalent information. (AIP)

Spectrophotometric observations of N galaxies at large redshift - PKS 0353+027, 3C 99, 3C 467

Spectrophotometric observations are presented for three N galaxies identified with the radio sources PKS 0353+027, 3C 99 (PKS 0358+00), and 3C 467 (PKS 2345+18). The systems are spectroscopically similar, showing high excitation and relatively rich emission-line spectra with redshifts of 0.602, 0.426, and 0.631, respectively. the object 3C 467 is observed to have small but significant difference between emission-line redshifts computed from forbidden and permitted lines, corresponding to a velocity difference of 300 kms s/sup -1/. PKS 0353+027 and 3C 467 are quite similar to the N system 3C 411 showing strong Mg ii lambda2799 which is considerably broader than the Balmer lines observed. Consideration of the O/H ratio derived from the ratios of the (O iii) lines and H..beta.. leads us to the conclusion that the nuclei of these galaxies must have electron densities n/sube/approximately-greater-than10/sup 6/ and T/sube/approx. =10,000 K unless the oxygen abundance is exceedingly low. The equivalent widths of H..beta.. for these systems are consistent with excitation by photoionization from the observed optical nonthermal continuum extrapolated to ionizing energies. The calculated absolute magnitudes for PKS 0353+027, 3C 99, and 3C 467 range from values for normal first-ranked cluster galaxies up to the lower luminosity quasi-stellar objects. (AIP)

The Absolute Magnitude of First-Ranked Cluster Galaxies as a Function of Cluster Richness

The conclusion is that no statistical theory based on real luminosity functions is capable of explaining the observed magnitude-richness relation. The data seem to require a uniqueness about the first few galaxies in clusters that makes their absolute luminosities nearly independent of cluster population. (AIP)

ON THE SURFACE BRIGHTNESS OF FIRST-RANKED CLUSTER GALAXIES

ABSTRACT It is shown that Sandage's arguments for a constant mean surface brightness of firstranked cluster ellipticals are incorrect. In addition, a cosmic dispersion of 0.29 mag is found and first-ranked galaxies in irregular clusters appear to have brighter than average surface brightness. The potential usefulness of a surface brightness-redshift plot as an important cosmological test is discussed. Key words: surface brightuesses of galaxies - clusters of galaxies - photometry of galaxies - cosmology