Redshifts of compact galaxies in systems of galaxies

82 compact galaxies with measured redshift present in systems containing partly normal galaxies have been found, using Zwicky's Catalogues and Morphological Catalogue. For them the mean residual redshift has been obtained. The chance probability for this result is 0.015. A high frequency of compact galaxies among those with large discrepant redshift is remarked. Relatively compact normal galaxies also reveal a positive mean value of . Redshift is correlated with magnitude in groups and pairs of compact galaxies, this depending in pairs on the linear separation and colours of the components. If a colour difference is present, the bluer member has the larger redshift in general. In contrast with the large luminosity deduced from the redshift for many field compacts, compact galaxies in systems are faint. The majority of the proposed associations between quasars and systems of normal galaxies are shown to be probably physical.     

On the relation between radius,luminosity, surface brightness,and surface density in elliptical galaxies

We have analyzed luminosity profiles of E galaxies studied by Strom and Strom in six clusters of galaxies. We have found a relationship between radius, luminosity, and surface brightness for galaxies in each of the clusters. A dependence of the zero point of the relation with the local projected density of galaxies is likewise found:r _{e proj} ^–0.14 L ^0.445 I _e ^–0.413 . This relationship implies (i) that there is not a universal luminosity profile for elliptical galaxies, (ii) the environmental variation of radius is larger than that produced by mergers of galaxies, (iii) distance to a galaxy can be estimated from apparent magnitude, surface brightness, angular size, and apparent local projected density of galaxies.     

Do morphological properties of interacting galaxies indicate that the latter are topological abelian higgs vorto-sources (vorto-sinks)?

We propose an Abelian Higgs model for spiral galaxies in which the latter are treated as topologically stable magneticvorto-sources (-sinks). The model is characterized by the minimum coupling between the electromagnetic vector potential and a scalar, complex-valued Higgs field that results - for an idealized cylindrically symmetric case - in a perpendicular to the galaxy's plane distribution of magnetic field strength whose total flux is a discrete-valued quantity - aninteger multiple of the elementary flux unit. Adopting the hypothesis that spiral arms trace the curves of a constant phase of the Higgs field we demonstrate that, for an almost-everywhere divergence-free vector potential, the arms acquire the observationally well-established form of logarithmic spirals whose woundness is here of an electromagnetic origin in the sense that it depends on the ratio between the specific volume-divergence of a galaxy and its total magnetic flux. The hypothesis further implies that the number of spiral arms is justtwice as that of magnetic flux quanta a galaxy possesses; the observed preponderance of two-armed spirals then simply reflects the fact that most galaxies carry single flux quantum which is energetically favourable for the vorto-sources (-sinks) whose disk-to-bulge radius ratio > 1. The latter property also leads to the process of galaxyfragmentation in the sense that a galaxy endowed withp magnetic flux quanta should fission into the topologically equivalent configuration consisting ofp singly-quantized galaxies.A unique possibility to test our model is provided by physically paired galaxies. Considering the simplest configuration consisting of spirals lying in the same plane and having equal in magnitude fluxes and volume-divergences we distinguish four topologically different distributions of the Higgs field phase which fairly well capture observed morphologies exhibited by double galaxies; we find, in particular, that of most frequent occurrence seem to be couples with anti-parallel orientation of magnetic field.Finally, we address the question of the periodicity in the distribution of galaxy redshifts and show that a discrete-valuedness of themass of spiral galaxies resulting from our model may serve as a starting point to solve this puzzling effect.     

Rotation curves for spiral galaxies in clusters and in the field

Rotation curves of spiral galaxies in clusters are compared with their counterparts in the field using three criteria: (1) inner and outer velocity gradients, (2)M/L gradients, and (3) Burstein's mass type methodology. Both H emission-line rotation curves and more extendedHi rotation curves are used. A good correlation is found between the outer gradient of the rotation curve and the galaxy's distance from the centre of the cluster, in the sense that the inner galaxies tend to have falling rotation curves while the outer galaxies, and field galaxies, tend to have flat or rising rotation curves. A correlation is also found between theM/L gradient across a galaxy and the galaxy's position in the cluster, with the outer galaxies having steeperM/L gradients. Mass types for field spirals are shown to be a function of both Hubble-type and luminosity, contrary to earlier results. The statistical difference between the distribution of mass types in clusters and in the field reported by Bursteinet al. is confirmed. These correlations indicate that the inner cluster environment can strip away some fraction of the mass in the outer halo of a spiral galaxy, or alternatively, may not allow the halo to form.     

The magnetic fields in M31, NGC 7331, NGC 2841, NGC 6946, and our galaxy

A time-independent model for the radial distributions of gas and magnetic field has been applied to the galaxies Milky Way, M31, NGC 7331, and NGC 2841, in order to explain the gaseous ring patterns in spiral galaxies, and to NGC 6946 to see if this model is valid for galaxies without a gaseous ring. The model takes the gas pressure as its input data and solves the MHD equations to calculate the magnetic field responsible for the gas distribution. This field has an azimuthal component only, and can be used to predict synchrotron radio emission. A discussion about the dependence of the synchrotron radiation profiles obtained upon the assumed relationN ₀(,B) for the cosmic-ray density per unit energy as a function of gas density and field strength, is here considered in detail. It is shown that a relation of the typeN ₀/B, which takes into account the loss of energy of the cosmic-relativistic electrons, yields good agreement with the observations.     

Flat Galaxies of the RFGC Catalog Detected in the HIPASS Survey

Data from the H I Parkes All-Sky Survey (HIPASS) of the southern sky in the neutral hydrogen line are used to determine the radial velocities and widths of the H I line for flat spiral galaxies of the Revised Flat-Galaxy Catalog (RFGC) seen edge-on. The sample of 103 flat galaxies detected in HIPASS is characterized by a median radial velocity of +2037 km/sec and a median width of the H I line at the level of 50% of maximum of 242 km/sec. For RFGC galaxies the 50% detection level in HIPASS corresponds to an apparent magnitude B _t = 14 ^m .5 or an angular diameter a = 2.9. The relative number of detected galaxies increases from 2% for the morphological types Sbc and Sc to 41% for the type Sm. The median value of the ratio of hydrogen mass to total mass for RFGC galaxies is 0.079. With allowance for the average internal extinction for edge-on galaxies, <B _t< = 0 ^m .75, the median ratio of hydrogen mass to luminosity, M _{H I}/L _B = 0.74 M /L , is typical for late-type spirals. Because of its small depth, HIPASS reveals only a few RFGC galaxies with previously unknown velocities and line widths.     

Determination of true velocity dispersion and the dark matter problem in clusters of galaxies

According to the convention normally followed the redshifts of the galaxies in a cluster are assumed to be of purely dopplerian origin. The resulting velocity dispersion, when used in the virial theorem, leads to a very large proportion of dark matter to be present in the galaxy clusters. However, the recently proposed model of velocity dependent cosmic drag cause redshifts of photons and it is necessary to develop a procedure to determine the true velocity dispersion from the gross redshift data. A method for this has been presented in the paper. Coma and Perseus clusters have been investigated using this procedure and theM/L ratios for both were found to be approximately of the order of 30, i.e., approximately the order ofM/L ratios for individual galaxies. A study of them -z relation indicates that the galaxies with higher redshifts have fainter magnitudes. Distortion of the redshift plots and the typical elongation of the core regions along the line-of-sight is also explained.     

cD galaxies of apparent supergiant sizes due to the curvature of space

By combining two two-dimensional subspaces, closed into themselves due to curvature, it is possible to create a model of three-dimensional space of the same properties. If the Universe is a space of this type, its effect is that of a monstrous lens. Close objects are observed to diminish according to the normal law of perspective; however, the remote galaxies are seen to be very highly magnified.The apparent angular size² of a galaxy is more than the size¹ in flat space according to relation:² =¹ cosec , where is the angular distance from the observer to the galaxy. The diameter² d of a galaxy in curved space must be in the same relation to a diameter¹ d with no curvature of space:² d=¹ d cosec . The apparent angular size² and diameter² d are distorted shapes in consequence of an optical illusion caused by the spatial curvature.It is necessary to distribute the multitude of galaxies into two parts in accordance with their location on the close or reverse hemihypersphere of the Universe. The minimum of apparent angular size² of a galaxy of diameter¹ d is at the equatorial zone.The most likely candidates for location in the reverse hemi-hypersphere are cD's of apparent supergiant sizes due, probably, to the curvature of space. The existence of supergiant sizes of galaxies is the second indirect proof, besides superluminal velocities, that the Universe is closed into itself through curvature. The third indirect evidence, i.e., inductive confirmation of the same fact, is the superposition of galaxies which need not inevitably be a new alternative to the present theories of collisions, cannibalism, merger, etc.The fourth indirect proof of the positive curvature of the Universe is the occurrence of background radiation, because that must vanish in hyperbolic space irrespective of its origin. The gravitational lens effect acquires another theoretical form, as usual, in the case of remote galaxies, because it is impossible to distinguish between gravitator and lensing image.     

Local Field of Galaxy Velocities

A sample of 145 galaxies having radial velocities relative to the centroid of the Local Group V _LG < 500 km/sec and estimated photometric distances D < 8 Mpc is considered. The field of peculiar velocities of these galaxies is estimated using the tensor of the local value of the Hubble constant H _ij , with principal values of 81:62:48 in km/sec·Mpc, which have a standard error of 4 km/sec·Mpc. The minor axis of the Hubble ellipsoid is oriented almost along the polar axis of the Local Supercluster, while the major axis forms an angle = (29 ± 5)° with the direction toward the center of the Virgo Cluster. Such a configuration of the peculiar-velocity field shows unsatisfactory agreement with the model of a spherically symmetric flow of galaxies toward the Virgo Cluster. Rotation of the Local Supercluster may be one reason for this difference. The peculiar velocities of galaxies within a volume with D < 8 Mpc are characterized by a dispersion _V = 74 km/sec, a considerable part of which is due to the virial motions of galaxies in groups and to distance errors. For field galaxies, located in a layer of 1 < D < 3 Mpc around the Local Group, the radial-velocity dispersion does not exceed 25 km/sec. The velocity—distance relation, constructed from the 20 closest galaxies around the Local Group with D < 3 Mpc and with errors (D) < 0.2 Mpc, exhibits the expected effect of gravitational deceleration. Using the estimate of R ₀ = (0.96 ± 0.05) Mpc for the observed radius of the zero-velocity sphere, we determined the total mass of the Local Group to be (1.2 ± 0.2)·10¹² M , which agrees well with the sum of the virial masses of the subgroups of galaxies around the Local Group and M31. The ratio of the Local Group's total mass (within R ₀) to its luminosity is M/L = (23 ± 4) M /L , which does not require the existence of supermassive dark halos around our Galaxy and M31.     

Ultraviolet (200 nm) observations of the nearby cluster of galaxies abell 1367

Ultraviolet (200 nm) observations of 120 galaxies are performed in a 1.8 square degree field centered on the A 1367 cluster with a 40 cm imaging telescope flown on a stabilized balloon-borne gondola. Total ultraviolet fluxes are obtained and used to derive the current Star Formation Rate (SFR) in the cluster galaxies with measured Hi masses. A good correlation is found between the SFR per unit area and the gas surface density, similar to that previously found for a sample of field galaxies (Donaset al., 1987), while the mean gas depletion time-scale (M _g/SFR) is probably shorter in the cluster than in the field.     

Estimating the Luminosity Function of M51-Type Galaxies

A new sample of M51-type galaxies consisting of 46 systems is used to estimate the B-band luminosity function. The luminosity function for the primary components of the systems can be described by a Schechter function with the parameters _* = (1.4±0.3)×10^-5 Mpc^-3, = -1.3^+0.4 _-0.3, and M _* = -20.3^+0.2 _-0.1. The values of the latter two parameters are comparable to those for isolated galactic pairs. The resulting estimate of the average density of M51-type galaxies is (4±3)% of the average density of isolated pairs for luminosities in the range -22^m.0<M<-16^m.0     

On the formation of superdense gaseous cores in the nuclei of disk galaxies — I

A model for the formation of superdense gaseous cores by accretion in the nuclei of disk galaxies has been proposed. Equations for radial flow of gas into the nucleus in the presence of aweak galactic magnetic field have been solved, and time scales for the accretion of an exploding mass in the nucleus (10⁹ M ) have been obtained under several different situations in the absence of any rotation. The time scales are found to lie in the range between a few times 10⁷ yr and 10⁸ yr. Such time scales have been proposed by some authors for repeated explosions in the nuclei of galaxies; they have also proposed that spiral arms in disk galaxies are repeatedly formed and destroyed over such time scales. It is shown that the presence of rotational velocities in the infalling gas practically destroys the efficiency of the accretion process unless such velocities are dissipated by frictional forces within the system. Viscosity of gas is the most obvious dissipative agent. The problem of accretion of a rotating viscous gas will be discussed in a subsequent paper.     

A catalog of isolated galaxy pairs with accurate radial velocities

The present paper is devoted to the construction of a catalog of isolated galaxy pairs from the Uppsala Galaxy Catalog (UGC), using accurate radial velocities. The UGC lists 12 921 galaxies to δ > ?2?30′ and is complete to an apparent diameter of 1′. The criteria used to define the isolated galaxy pairs are based on velocity, interdistance, reciprocity and isolation information. A peculiar investigation has allowed to gather very accurate radial velocities for pair members, from high quality HI and optical measurements (median uncertainty on velocity differences 10 kms^?1). Our final catalog contains 1005 galaxy pairs with ρ > 2.5, of which 509 have ρ > 5 (50% of the pairs, i.e. 8%of the UGC galaxies) and 273 are highly isolated with ρ > 10 (27% of the pairs, i.e. 4% of the UGC galaxies). Some global properties of the pair catalog are given.     

Far infrared emission from galaxies

Until recently far infrared (FIR) observations of galaxies were limited to about a dozen bright and/or active galaxies. New photometric data has become available from Infrared Astronomical Satellite (IRAS) on 33 galaxies (most of them faint) from IRAS Circular Nos. 1, 2, and 3 The FIR spectra of these galaxies are similar. The far infrared fluxF _FIR in the wavelength interval 9–118 m of the brighter galaxies is seen to be correlated with the integrated optical magnitudeB _T ⁰ . The 12 and 25 m fluxes of these galaxies exhibit the same dependence onB _T ⁰ as the 10 and 21 m fluxes from Seyferts and other emission-line galaxies. This suggests that the galaxies detected by IRAS are some type of active galaxies in accord with the high percentage of these galaxies predicted by Lock and Rowan-Robinson (1983).     

Number-magnitude count for galaxies at the South Galactic Pole

COSMOS measures on a deep UK Schmidt Telescope Plate have been used to obtain the number-magnitude count for galaxies in a field of 14.6 square degrees near the South Galactic Pole. The results are in excellent agreement with data for the North Galactic Pole for galaxies fainter thanB=18.0, indicating no large-scale differences between north and south. A deficiency in numbers is observed for galaxies withB16.0. This is comparable to the deficiency atB17.5 for counts at the North Galactic Pole and supports the suggested asymmetry of the bright galaxy distribution between north and south galactic poles.     

Surface Density of Bright, Active Extragalactic Objects

A new sample of local, active extragalactic objects has been compiled: a combined sample that is the sum of two samples, of Sy1 galaxies and of quasars from Markarian's survey and quasars from the Bright Quasar Survey. A log N(<B)-B relation is constructed for the new sample of active galaxies, limited to the apparent stellar magnitude B = 15 ^m .5. It can be represented by a straight line with a slope = 0.60 ± 0.06. It is a good extension, without a noticeable jog, of the analogous relationship for the Hamburg—ESO survey, which has a slope = 0.59 ± 0.04. The combined surface density of bright active galaxies and quasars down to B = 15 ^m .5 is 0.01 per square degree.     

The gravitational field of flat galaxies

A set of bi-orthogonal pairs of functions is derived which is especially suited for the calculation of the gravitational field of flat galaxies. The functions are Hankel tranforms of associated Laguerre functions, or Hankel-Laguerre functions. They can be calculated by means of recurrence relations, which are derived from a generating function.Numerical computations are most efficiently performed using a related set of Chebyshev type functions, which have more economic recurrence relations. The necessary algorithms for efficient calculation of the field are derived using the properties of Hankel-Laguerre functions.This field calculation, can be used for a relatively cheap and simple computer simulation of galaxies.     

The maximum and minimum masses of galaxies

Galaxies may have formed by fragmentation in a collapsing cloud of very large mass. The most massive galaxies were formed from fragments which were nearly but not quite opaque: the least massive galaxies were formed from fragments about as large as the Jeans mass. If the maximum mass of galaxies is 10¹³ M , then the minimum mass should be 10⁶ M .     

On the direction of rotation of the spirals in galaxies

The detection of trailing arms in twenty spiral galaxies, completed by the 60s, allowed one to suggest the overwhelming prevalence of this sense of rotation. Pasha and Dambis (1982) have recently determined the direction of rotation in a further 54 galaxies and found two leading spirals, NGC 4490 and NGC 5395. The current sample of galaxies with an established sense of rotation contains 79 trailing and two leading systems. The two spirals found to be leading belong to M51 type galaxies.In this paper we present a more detailed investigation of the system NGC 4490/85 which confirms that the arms in NGC 4490 are leading. Statistics are invoked to estimate a probable percentageX _p and an upper limitX _up of galaxies with leading arms. It gives, for 79 trailing and two leading spirals, the valuesX _p 3.5% andX _up 8.2%.     

Elliptical galaxies: Can rotation be effective in determining their shapes?

The present paper aims to investigate the modelling of real galaxies—at least as a zeroth order approximation—in such a way that rotation can be effective in determinating their intrinsic shape. The connection between the presence of isotropy in the pressure (or equivalently in the peculiar velocity) and observed gradients of metal content in most galaxies is briefly discussed, next solid-body rotating EC polytropes are proposed as acceptable models and the limits of this approach are considered. Appropriate estimates of both the theoretical ratio of some characteristic projected rotational velocity to some characteristic projected peculiar velocity,V/, and the apparent ellipticity,ê ^*, are calculated for the whole range of axis orientations, then the behaviour ofV/ vsê ^* is compared with observations. We find that real galaxies seem to display according to two distinct sequences; a main fraction of bright ellipticals may be reproduced by both axisymmetric configurations with all degrees of central condensation and triaxial configurations with lower degree of central condensation, while the remaining bright ellipticals, SA and SB bulges and ellipticals fainter thanM _B =–20.8 are seen to be fitted by axisymmetric configurations with lower degree of central condensation only. Some implications of such results are also reported and discussed. Finally, using qualitative considerations we show that solid-body rotating EC polytropes may lead to a naive model of galactic evolution, which enables both to reconcile observed gradients of metal content with the trend exibited byV/ vsê ^*, and to simulate—at least as a zeroth order approximation—the morphological sequence of real galaxies.