Showing papers on "Brightest cluster galaxy published in 1973"
TL;DR: In this article, the neutral hydrogen content of 25 galaxies in the Virgo cluster was measured using the Mark I and Mark II radio telescopes, and the results indicated that on average the cluster galaxies are deficient in neutral hydrogen by a factor of approximates 0.63.
Abstract: Twenty-one centimetre wavelength measurements, using the Mark I and Mark II radio telescopes, were made of the neutral hydrogen content of 25 galaxies in the Virgo cluster. Spectra of some of the brighter galaxies are shown, and the neuiral hydrogen parameters of each galaxy are given in tabular form. A comparison of the neutral hydrogen mass-to-luminosity ratio and the neutral hydrogen surface density for the Virgo cluster galaxies with field galaxies indicates that on average the cluster galaxies are deficient in neutral hydrogen by a factor of approximates 0.63. Calculations of galactic collision times suggest that collisions are likely to be responsible for the deficiency of gas in the Virgo cluster galaxies at the present epoch. (auth)
101 citations
Journal Article•
TL;DR: In this article, two models for the formation of tailed radio sources like 3C 129 are developed, one of which is a modification of current models of normal symmetric double radio sources, with the effects of the motion of the parent galaxy and of the thermal pressure of the intracluster gas included.
Abstract: Two medels for the formation of tailed'' radio sources like 3C 129 are developed. Both models assume that the tails are the result of the rapid motion of an active galaxy through the relatively dense gas in a cluster of galaxies. The first model is a modification of current models of normal symmetrical double radio sources, with the effects of the motion of the parent galaxy and of the thermal pressure of the intracluster gas included. The second model assumes that the galaxy has a long, permanently attached, magnetospheric tail, similar to the geomagnetic tail, generated by the action of the intracluster gas flow on the intrinsic magnetic field of the galaxy. This tail is illuminated at intervals by outbursts of high energy electrons from the galaxy. An attempt is made to fit both models to 3C 129 to see if they give a good explanation of the observed characteristics of this source, and to determine the physical conditions in the intracluster gas. While both models give good fits to the shape of the tail, the magnetospheric model gives a better fit to the observed spectral indices, more » as well as relbes ia the interpretation of the polarization solving some difficulties in the interpretation of the polarization of the radio emission of 3C 129. The relation of the models to normal symmetric double radio sources, and to intermediate cases like 3C 465 is discussed. The derived values of the intracluster density and temperature are considered. (auth) « less
58 citations
52 citations
TL;DR: In this article, photoelectric UBV observations were obtained for 92 Markarian galaxies and an additional five Seyfert galaxies to study the colors of the continuous spectra in these objects.
Abstract: Photoelectric UBV observations were obtained for 92 Markarian galaxies and an additional five Seyfert galaxies to study the colors of the continuous spectra in these objects. A total of 28 Seyfert galaxies, 42 other galaxies with bright blue nuclei, and 27 diffuse galaxies were included. Multiaperture observations are presented for seven of these galaxies. It was found that galaxies spectroscopically classified as Seyfert galaxies because of broad nuclear emission lines have UBV colors corresponding to nonthermal continua, but the numerous Markarian galaxies with bright nuclei having narrow emission lines do not have such colors; instead, the ultraviolet continua of these galaxies apparently arise from hot stars. New spectroscopic and photographic observations are also presented for some Markarian galaxies of particular interest, including Markarian 3 and 205. (auth)
50 citations
45 citations
TL;DR: Abell 2670 is a rich, compact cluster of galaxies dominated by a very large central cD galaxy, which was used to obtain its luminosity function, which resembles that of Coma and other clusters as mentioned in this paper.
Abstract: Abell 2670 is a rich, compact cluster of galaxies dominated by a very large central cD galaxy. A new method of galaxy photometry was used to obtain its luminosity function, which resembles that of Coma and other clusters. The cD galaxy has an elliptical-galaxy core and a diffuse envelope which was traced to almost 1 Mpc and which probably fills the cluster. On the assumption that it does, the mass-to-light ratio of the cluster is 255 plus or minus 117 M/sub sub solar //L/sub sub solar /. (au th)
35 citations
35 citations
32 citations
TL;DR: The radio galaxy 3C 66 has been mapped at frequencies of 1.4, 2.7, and 5.0 GHz with the Cambridge One-Mile telescope and at 5.5GHz with the 5-km telescope.
Abstract: The radio galaxy 3C 66 has been mapped at frequencies of 1.4, 2.7, and 5.0 GHz with the Cambridge One-Mile telescope and at 5.0 GHz with the 5-km telescope. The main source (3C 66B) consists of a compact central component less than 0.8 kpc in diameter, coincident with the nucleus of the galaxy, together with very extended regions of low brightness emission on each side. The most remarkable feature of the source is a narrow jet of emission, approximately 30 kpc in length, linking the galactic nucleus to one of the extended regions and consisting of a number of compact components, less than 1 kpc in diameter, superimposed on a weak continuous background. The structure of 3C 66B, which suggests that energy is continuously supplied by the nucleus to the outer components, has a simple interpretation in terms of the bubble model recently proposed for more powerful, double radio galaxies. A further source (3C 66A), less than 1.6'' in diameter, is probably unrelated to 3C 66B. (auth)
27 citations
TL;DR: In this paper, a measurement of the spatial power spectrum of the cosmic light on a series of photographic plates taken with the Palomar 48-inch (122cm) Schmidt camera is presented.
Abstract: Because galaxies cluster in space, the cosmic background light due to galaxies is not smoothly distributed on the night sky. Part I predicts spatial power spectra for the cosmic light fluctuations, based on the luminosity function for nearby galaxies and on the dumpiness of the galaxy distribution derived from galaxy counts. Part II describes a measurement of the spatial power spectrum of the cosmic light on a series of photographic plates taken with the Palomar 48-inch (122cm) Schmidt camera. This power spectrum is interpreted to provide a measure of the covariance of the galaxy distribution and the mean emissivity of galaxies in space.
23 citations
TL;DR: Isophotes, luminosity profiles, and photometric parameters of the brightest southern Seyfent galaxy NGC 1566, revised type SAB(s)bc, are derived from long and short-exposure photographs taken with the Mount Stromlo 75cm reflector and the Cordoba 152cm reflectors as mentioned in this paper.
Abstract: Isophotes, luminosity profiles, and photometric parameters of the brightest southern Seyfent galaxy NGC 1566, revised type SAB(s)bc, are derived from long- and short-exposure photographs taken with the Mount Stromlo 75-cm reflector and the Cordoba 152-cm reflector. (WDM)
TL;DR: Mean relations for the run of radius-parameter and central surface brightness with absolute magnitude are presented for E-SO galaxies in the cores of Abell clusters 754, 1367, and 2065.
Abstract: Mean relations for the run of radius-parameter and central surface brightness with absolute magnitude are presented for E--SO galaxies in the cores of Abell clusters 754, 1367, and 2065. These data are combined with the adjusted results of Fish (1964) for E galaxies in the Virgo cluster, Holmberg (1969) for nearby E- SO galaxies, and Brookes and Rood (1971) for E galaxies in cluster 1656 to show that the mean relations may differ significantly between clusters. No clear connection with cluster classification is evident. In all clusters, it appears that the fainter galaxies have been tidally distended. The use of the radius--parameter versus magnitude diagram as a relative-distance indicator suggests that redshift is not a good distance indicator for the Virgo cluster, giving a substantial peculiar velocity, and gives support to Abell's cluster fitting method. The central surface brightnesses of first-ranked cluster galaxies exhibit a scatter (m.e.) of about 0.8 mag about the average. These last two results are in disagreement with recent findings by Sandage.
TL;DR: In this article, surface photometry of the elliptical companion of NGC 5846 has been performed, showing that it lacks an extended envelope but instead has a profile resembling that of a low- concentration star cluster.
Abstract: Surface photometry of the elliptical companion of NGC 5846 shows that it lacks an extended envelope but instead has a profile resembling that of a low- concentration star cluster. It appears to be tidally limited by its giant neighbor. (auth)
TL;DR: In this article, neutral hydrogen measurements were made for 29 galaxies with the Mark I and Mark II telescopes, mainly early types, although four Seyferts and a group of peculiar and other interesting objects were included.
Abstract: Neutral hydrogen measurements were made for 29 galaxies with the Mark I and Mark II telescopes. The galaxies were mainly early types, although four Seyferts and a group of peculiar and other interesting objects were included. Spectra of the more intense galaxies are shown. An interesting result is the large neutral hydrogen content of the early-type galaxies (de Vaucouleurs types - 3 to +l) compared with the trend of neutral hydrogen contents indicated by the late-type galaxies. The importance of this result for theories of galactic evolution is stressed. The neutral hydrogen content and velocity spread of the Seyfert and peculiar galaxies are found to be consistent with their morphological types and appear to be unaffected by their optical peculiarities. (auth)
TL;DR: A photographic 200-inch plate of the compact cluster of galaxies Shakhbazian I is presented and discussed in this article, where the mass-to-light ratio of the cluster is 0.3-0.5.
Abstract: A photographic 200-inch plate of the compact cluster of galaxies Shakhbazian I is presented and discussed. The size of the cluster, the nature of the galaxies and the very small velocity dispersion all make this cluster unique. The mass-to-light ratio of the cluster is 0.3-0.5.
TL;DR: In this article, it was shown that the most convincing evidence that the galaxies are actually at the distances indicated by the Doppler interpretation of their redshifts has been the discovery of normal galaxies at small angular separations from QSOs that have essentially the same red shifts as the galaxies.
Abstract: It is stated that the most convincing demonstration that QSOs are actually at the distances indicated by the Doppler interpretation of their redshifts has been the discovery of normal galaxies at small angular separations from QSOs that have essentially the same red shifts as the galaxies. Five examples of QSOs or related objects apparently in association with galaxies or clusters of galaxies are known, but an additional example of a galaxy having a redshift similar to that of an adjoining bright QSO is here reported. The QSO is 4C37.13, which has an estimated visual magnitude of 15.5 and a redshift z = 0.370, and a faint galaxy lies 9.9'' east and 2.4'' south of the QSO. A spectrogram of this galaxy was obtained using an RCA image intensifier with the Cassegrain spectrograph of the Mauna Kea 224 cm. telescope, indicating a mean redshift z = 0.3736. The QSO was observed with the same equipment and its redshift found to be z = 0.3708. (UK)
Journal Article•
TL;DR: In this article, the radial velocity difference between the companion and the main galaxies is shown to be equal to 90 km s/sup -1/ε 1/ε −1.
Abstract: The study of the differential velocities of companion galaxies with respect to their main galaxy made by Arp is extended to the nearby groups of galaxies in which the main galaxy is at least 50% more luminous than each of the others. An effect similar to the one found by Arp is brought to light. The mean value of the radial velocity difference between the companion and the main galaxies is equal to 90 km s/sup -1/. Three possible observational bias are considered which do not appear to be responsible of the observed effect. (auth)
Journal Article•
TL;DR: In this article, the formation of galaxies was triggered off by energy density fluctuations in the hadronic era of the universe, and the mass spectrum of galaxies and galaxies in clusters was given by the thermodynamics of strong interactions.
Abstract: If the formation of galaxies was triggered off by energy density fluctuations in the hadronic era of the universe, then the mass spectrum of galaxies (and galaxies in clusters) is given by the thermodynamics of strong interactions. An observational test is proposed.
Journal Article•
TL;DR: In this paper, the relation between the redshift of galaxies and their surface brightness was studied in clusters, groups, and pairs, and several surfuce brightness parameters were examined, including elliptical face brightness and steep edge-gradient of intensity.
Abstract: The relation between the redshift of galaxies and their surface brightness was studied in clusters, groups, and pairs. Several surfuce brightness parameters were examined. In clusters and pairs redshift increased with mean surface brightness of the galaxy, but in groups such a dependence was not found. The following galaxies showed large frequencies of positive residual redshifts with respect to the mean redshift of the system: a) elliptical face brightness and steep edge-gradient of intensity: (c) components in double and multiple galaxies with smaller concentration of light toward the center than is the average for the system; (d) galaxies compact in the sense of the word used in CGCG (Zwicky et al., 1961-1968); (e) Sb and Sc galaxies with low nuclear surface brightness. Similar features of surfuce brightness often occurred in galaxies with discrepant redshifts. (auth)
TL;DR: In this paper, a mechanism for the formation of dwarf galaxies in the vicinity of active radio galaxies is proposed, which suggests that the Coma cluster of galaxies may be bound by intergalactic halo-type stars.
Abstract: A mechanism is proposed for recent formation of dwarf galaxies in the vicinity of active radio galaxies. In the cores of rich clusters these dwarf galaxies are stripped of gas and eventually suffer tidal disruption. This leads us to suggest that the Coma cluster of galaxies may be bound by intergalactic halo-type stars.
TL;DR: A systematic variation of redshifts is found across the chain of one of these groups, Abell 2247, and several interpretations are discussed in this article, but these two groups have previously been assigned to the same cluster.
Abstract: Redshifts are reported for two groups of galaxies. Although these two groups have previously been assigned to the same cluster, their redshifts indicate that they are not associated. A systematic variation of redshifts is found across the chain of one of these groups, Abell 2247, and several interpretations are discussed. (auth)
TL;DR: In this paper, the distribution of rotational angular momentum in the Virgo cluster is analyzed using the direction of a galaxy's spiral winding, which is assumed to be a function of the galaxy's rotation.
Abstract: On the assumption that the direction of a galaxy's spiral winding defines the direction of its rotational angular momentum vector, 101 spiral galaxies in the area of the Virgo cluster are used to analyze the distribution of rotational angular momentum. The main body of the cluster is very isotropic, but ffie "southern wing" shows a marginal anisotropy. Key words: rotations of galaxies - clusters of galaxies
TL;DR: In this paper, the authors reported redshifts for 27 outlying galaxies in Coma, including four galaxies with emission lines and 24 galaxies with redshift typical for Coma galaxies.
Abstract: Redshifts are reported for 27 outlying galaxies in Coma. Twentyfour have redshifts typical for Coma galaxies, and 11 galaxies show emission lines. (auth)
Journal Article•
TL;DR: In this paper, a detailed 1415 MHz brightness and polarization distribution for 3C 129, NGC 1265, and IC 310 with a resolution of 23" x 30" is presented.
Abstract: Detailed 1415 MHz brightness and polarization distributions are presented for 3C 129, NGC 1265, and IC 310 with a resolution of ~23" x 30". For each of the sources the percentage polarization increases with distance from the optical galaxy. A comparison of these data with previous 408 MHz measurements gives useful spectral information. It is suggested that 3C 129.1 is another example of a head-tail galaxy. (auth)
TL;DR: In this article, the authors evaluated the newly published Uhuru catalog, revealing significant number of rich clusters associated with X-ray sources, including the Virgo, Coma, and Perseus clusters.
Abstract: Evaluation of the newly published Uhuru catalog, revealing significant number of rich clusters associated with X-ray sources. Combined with earlier observations of X-ray emission from the Virgo, Coma, and Perseus clusters, this suggests that most, if not all, rich clusters include an X-ray emission region of large size and of net luminosity from 10 to the 43rd to 10 to the 44th ergs/sec.