arXiv subjects

Wlodzimierz Godlowski

Publications and source records attributed to Wlodzimierz Godlowski.

At least 19 recordsLinked to original sources

arXiv2020

The influence of stellar objects mass distribution on their gravitational fields

We study the influence of the astronomical objects masses randomness on the distribution function of their gravitational fields. Based on purely theoretical arguments and comparison with extensive data, collected from observations and numerical simulations, we have shown that while mass randomness does not alter the non-Gaussian character of the gravitational fields distribution, it changes the dependencies of mean angular momenta of galaxies and clusters on their richness. The specific form of above dependence is determined by the interplay of mass distribution character and different assumptions about cluster morphology. We trace the influence of masses distribution on the time evolution of stellar objects angular momenta in CDM and $Λ$CDM models. Our theoretical predictions are in very good coincidence with the statistical results derived both from observational data and numerical simulations.

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arXiv2019

Investigation of the orientation of galaxies in clusters: the importance, methods and results of research

Various models of structure formation can account for various aspects of the galaxy formation process on different scales, as well as for various observational features of structures. Thus, the investigation of galaxies orientation constitute a standard test of galaxies formation scenarios since observed variations in angular momentum represent fundamental constraints for any model of galaxy formation. We have improved the method of analysis of the alignment of galaxies in clusters. Now, the method allowed analysis both position angles of galaxy major axes and two angles describing the spatial orientation of galaxies. The distributions of analyzed angles were tested for isotropy by applying different statistical tests. For sample of analyzed clusters we have computed the mean values of analyzed statistics, checking whether they are the same as expected ones in the case of random distribution of analyzed angles. The detailed discussion of this method has been performed. We have shown how to proceed in many particular cases in order to improve the statistical reasoning when analyzing the distribution of the angles in the observational data. Separately, we have compared these new results with those obtained from numerical simulations. We show the powerful of our method on the example of galaxy orientation analysis in 247 Abell rich galaxy clusters. We have found that the orientations of galaxies in analyzed clusters are not random. It means that we genuinely confirmed an existence of the alignment of galaxies in rich Abells' galaxy clusters. This result is independent from the clusters of Bautz-Morgan types.

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arXiv2016

The Binggeli effect

We found the alignement of elongated clusters of BM type I and III (the excess of small values of the Δθangles is observed), having range till about 60Mpc/h. The first one is probably connected with the origin of supergiant galaxy, while the second one with environmental effects in clusters, originated on the long filament or plane.

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arXiv2015

The distribution of galaxies gravitational field stemming from their tidal interaction

We calculate the distribution function of astronomical objects (like galaxies and/or smooth halos of different kinds) gravitational fields due to their tidal in- teraction. For that we apply the statistical method of Chandrasekhar (1943), used there to calculate famous Holtzmark distribution. We show that in our approach the distribution function is never Gaussian, its form being dictated by the potential of interaction between objects. This calculation permits us to perform a theoretical analysis of the relation between angular momentum and mass (richness) of the galaxy clusters. To do so, we follow the idea of Catelan & Theuns (1996) and Heavens & Peacock (1988). The main difference is that here we reduce the problem to discrete many-body case, where all physical properties of the system are determined by the interaction potential V(r_ij). The essence of reduction is that we use the multipole (up to quadrupole here) expansion of Newtonian potential so that all hydrodynamic, "extended" characteristics of an object like its density mass are "integrated out" giving its "point-like" charac- teristics like mass and quadrupole moment. In that sense we make no difference between galaxies and smooth components like halos. We compare our theoretical results with observational data.

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arXiv2014

Orientation of galaxies in structures

The investigation of the orientation of galaxies is a standard test concerning to scenarios of galaxy formation, because different theories of galaxy formation make various predictions regarding to the angular momentum of galaxies. The new method of analysis of the alignment of galaxies in clusters was proposed in the paper Godlowski (2012) and now is improved. We analyzed the distribution of the position angles of the galaxy major axes, as well as the distribution of two angles describing the spatial orientation of galaxy plane, which gives the information about galaxy angular momenta. We discuss the orientation of galaxies in groups and clusters of galaxies. The results show the dependence of the alignment with respect to clusters richness. The implications of the results for theories of galaxy formation are discussed as well.

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arXiv2013

Some aspects of the orientation of galaxies in clusters

The analysis of Tully's groups of galaxies belonging to the Local Supercluster (LSC) was performed. In the 1975 Hawley and Peebles presented the method for investigations of the galaxies orientation in the large structures. In our previous papers statistical test proposed by Hawley and Peebles for investigation of this problem was analyzed in details and some improvements were suggested. On this base the new method of the analysis of galactic alignment in clusters was proposed. Using this method, Godłowski (2012) analyzed the orientation of galaxies inside Tully's group founding no significant deviations from isotropy both in orientation of position angles and $δ_D$ and $η$ angles as well, giving the spatial orientation of galaxy planes. In the present paper we examined carefully and methodically the dependence of alignment in Tully's groups on morphological type of galaxies. Moreover, we discussed the consequences of different approximation of "true shape" of the galaxies for different morphological types, possible influence of this problem for investigation of spatial orientation of galaxies. In addition, we discussed the implications of the obtained results for the theory of galaxy formation as well.

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arXiv2013

The investigations of anisotropy in orientations of galaxies

In 1994 Parnovsky, Karachentsev and Karachentseva suggested a modified method for investigation of the orientations of galaxies. Using this method they analyzed galaxies from the UGC and ESO catalogues, as well as from their's own catalogue inclusive of flat, edge-on galaxies. They found statistically significant anisotropy in the galaxies orientations'. In 1995 Flin suggested that this anisotropy has to be specific to LOcal Supercluster (LSC) In the present paper, using the method proposed by Parnovsky, Karachentsev and Karachentseva in 1994, we analyzed orientation of galaxies in the sample of galaxies belonging to LSC founding only a weak anisotropy. The relation of this method to Hawley and Peebles (1975) method of the investigation of the orientation of galaxies was discussed as well.

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arXiv2012

Comments on environmental effects in the origin of angular momenta in galaxies

We examine the orientations of galaxies in 43 rich Abell galaxy clusters belonging to superclusters and containing at least 100 members in the considered area as a function of supercluster multiplicity. It is found that the orientation of galaxies in the analyzed clusters is not random and the alignment decreases with supercluster richness, although the effect is statistically significant only for azimuthal angles. The dependence of galaxy alignment on cluster location inside or outside a supercluster and on supercluster multiplicity clearly shows the importance of environmental effects on the origin of galaxy angular momenta. The comparison with alignment of galaxies in a sample of rich Abell clusters not belonging to superclusters is made too.

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arXiv2012

Problems of Clustering of Radiogalaxies

We present the preliminary analysis of clustering of a sample of 1157 radio-identified galaxies from Machalski & Condon (1999). We found that for separations $2-15 h^{-1}$Mpc their redshift space autocorrelation function $ξ(s)$ can be approximated by the power law with the correlation length $\sim 3.75h^{-1}$Mpc and slope $γ\sim 1.8$. The correlation length for radiogalaxies is found to be lower and the slope steeper than the corresponding parameters of the control sample of optically observed galaxies. Analysis the projected correlation function $Ξ(r)$ displays possible differences in the clustering properties between active galactic nuclei (AGN) and starburst (SB) galaxies.

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arXiv2012

Constraints on cosmological models from strong gravitational lensing systems

Strong lensing has developed into an important astrophysical tool for probing both cosmology and galaxies (their structure, formation, and evolution). Using the gravitational lensing theory and cluster mass distribution model, we try to collect a relatively complete observational data concerning the Hubble constant independent ratio between two angular diameter distances $D_{ds}/D_s$ from various large systematic gravitational lens surveys and lensing by galaxy clusters combined with X-ray observations, and check the possibility to use it in the future as complementary to other cosmological probes. On one hand, strongly gravitationally lensed quasar-galaxy systems create such a new opportunity by combining stellar kinematics (central velocity dispersion measurements) with lensing geometry (Einstein radius determination from position of images). We apply such a method to a combined gravitational lens data set including 70 data points from Sloan Lens ACS (SLACS) and Lens Structure and Dynamics survey (LSD). On the other hand, a new sample of 10 lensing galaxy clusters with redshifts ranging from 0.1 to 0.6 carefully selected from strong gravitational lensing systems with both X-ray satellite observations and optical giant luminous arcs, is also used to constrain three dark energy models ($Λ$CDM, constant $w$ and CPL) under a flat universe assumption. For the full sample ($n=80$) and the restricted sample ($n=46$) including 36 two-image lenses and 10 strong lensing arcs, we obtain relatively good fitting values of basic cosmological parameters, which generally agree with the results already known in the literature. This results encourages further development of this method and its use on larger samples obtained in the future.

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arXiv2011

Remarks on the methods of investigations of alignment of galaxies

In the 1975 Hawley and Peebles gave the proposal to use three statistical tests for investigations of the galaxies orientation in the large structures. Nowadays, it has been considered as the standard method of searching for galactic alignments. In the present paper we analyzed the tests in details and proposed a few improvements. Basing on the improvements, the new method of analysis of the alignment of galaxies in clusters is proposed. The power of this method is demonstrated on the sample of 247 Abell clusters with at least 100 objects in each. The distributions of the position angles for galaxies in each cluster are analyzed using statistical tests: $χ^2$, Fourier, autocorrelation and Kolmogorow test. The mean value of analyzed statistics is compared with theoretical predictions as well as with results obtained from numerical simulations. We performed 1000 simulations of 247 fictious clusters, each with numbers of galaxies the same as the real ones. We found that orientations of galaxies in analyzed clusters are not random i.e. that there exists an alignment of galaxies in rich Abell galaxy clusters.

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arXiv2011

Some observational aspects of the orientation of galaxies

We investigated the sample of galaxies belonging to the Tully groups of galaxies. We analyzed the orientation of galaxies inside the group. We did not found significant deviation from isotropy both in orientation of position angles and angles $δ_D$ and $η$ giving the spatial orientation of galaxy planes. Moreover we analyzed consequences of different approximation of "true shape" of galaxies and showed possible influence of this problem for investigation of spatial orientation of galaxies. Implications of the obtained results for theory of galaxy formation was discussed as well.

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arXiv2011

The environmental effects in the origin of angular momenta of galaxies

We study the galaxy alignment in the sample of very rich Abell clusters located in and outside superclusters. The statistically significant difference among investigated samples exists. We found that in contrast to whole sample of cluster, where alignment increase with the cluster richness, the cluster belonging to the superclusters does not show this effect. Moreover, the alignment decreased with the supercluster richness. One should note however that orientations of galaxies in analyzed clusters are not random, both in the case when we analyzed whole sample of the clusters and only clusters belonging to the superclusters. The observed trend, dependence of galaxy alignment on both cluster location and supercluster richness clearly supports the influence of environmental effects to the origin of galaxy angular momenta.

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arXiv2011

Some properties of galaxy structures

We analysed some properties of galaxies structures based on PF Catalogue of galaxy structures (Panko & Flin 2006) and Tully NBG Catalog (Tully 1988) At first, we analyzed the orientation of galaxies in the 247 optically selected rich Abell clusters, having in the area considered as cluster at least 100 members. The distribution of the position angles of the galaxy as well as two angles describing the spatial orientation of galaxy plane were tested for isotropy, applying three statistical tests. We found that anisotropy increases with the number of member galaxies, which means there exists the relation between anisotropy and cluster richness. We do not find connection of galaxy alignment and Bautz - Morgan morphological type of parent cluster. The statistically marginal relation between velocity dispersion and cluster richness was observed. However it was found that velocity dispersion decreases with Bautz - Morgan type at almost $3 σ$ level. Separately we analyzed ellipticities for 6188 low redshift ($z < 0.18$) poor and rich galaxy structures which have been examined along with their evolution. Finally we analysed the Binggeli effect. The orientation of galaxy groups in the Local Supercluster (LSC), is strongly correlated with the distribution of neighbouring groups in the scale till about 20 Mpc. During analyses of galaxy structures from PF catalogue the situation was quite different. The efect is observed only for more elongated structures ($e \le 0.3$). The range of the distance in which the effect was observed, was estimated as about $60 h^{-1} MPc$.

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arXiv2011

Global and Local Effects of Rotation: Observational Aspects

In the paper we discussed the observational aspects of rotation in the Universe on different scales. We show dependence between the angular momentum of the structures and their size. The presented observational situation is that the galaxies, their pairs and compact groups have a non-vanishing angular momentum. In the structures of mass corresponding to groups of galaxies, this feature has not been found, while in the clusters and superclusters alignment of galaxy orientation has been actually found. Also we know that galaxies have net angular momentum due to the fact that we actually measure the rotation curves of galaxies. These facts lead to the conclusion that theories which connect galaxy angular momentum with its surrounding structure are at some extend favored by data. We show that in the light of scenarios of galaxy formations this result could be interpreted as an effect of tidal forces mechanism, but it is also consistent with Li's model, in which galaxies form in the rotating universe. The theoretical and observational aspects of possible global rotation of the Universe were discussed as well.

astro-ph.CO↗

arXiv2010

The Orientation of Galaxies in Galaxy Clusters

We present an analysis of the spatial orientations of galaxies in the 247 optically selected rich Abell clusters, having in the considered area at least 100 members. We investigated the relation between angles giving information about galaxy angular momenta and the number of members in each structure. The position angles of the galaxy major axes, as well as two angles describing the spatial orientation of galaxy plane were tested for isotropy, by applying three different statistical tests. It is found that the values of statistics increase with the amount of galaxies' members, which is equivalent to the existence of the relation between anisotropy and number of galaxies in cluster. The search for connection between the galaxies alignments and Bautz - Morgan morphological types of examined clusters gave weak dependence. The statistically marginal relation between velocity dispersion and cluster richness was observed. In addition, it was found that the velocity dispersion decreases with Bautz - Morgan type at almost 3$σ$ level. These results shows the dependence of alignments with respect to clusters' richness, which can be regarded as environmental effect.

astro-ph.CO↗

arXiv2009

Orientation of the galaxy groups in the Local Supercluster

The paper discusses the problem of the orientation of galaxies in groups in the Local Supercluster (LSC). The existence of the preferred orientation of galaxy group is shown. We found that the orientation of galaxy groups in the Local Supercluster in the scale till about 20 Mpc is strongly correlated with the distribution of neighbouring groups. The line joining the two brightest galaxies is in alignment with both the group major axes and the direction toward the centre of the LSC, i.e. Virgo cluster. These correlations suggest that two brightest galaxies were formed in filaments of matter directed towards the protosupercluster centre. Afterwards, the hierarchical clustering leads to aggregation of galaxies around these two galaxies. Our results are in agreement with the predictions of numerical simulations.

astro-ph.CO↗

arXiv2009

The orientations of galaxy groups and formation of the Local Supercluster

We analysed the orientation of galaxy groups in the Local Supercluster (LSC). It is strongly correlated with the distribution of neighbouring groups in the scale till about 20 Mpc. The group major axis is in alignment with both the line joining the two brightest galaxies and the direction toward the centre of the LSC, i.e. Virgo cluster. These correlations suggest that two brightest galaxies were formed in filaments of matter directed towards the protosupercluster centre. Afterwards, the hierarchical clustering leads to aggregation of galaxies around these two galaxies. The groups are formed on the same or similarly oriented filaments. This picture is in agreement with the predictions of numerical simulations.

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