Перегляд за Автор "Flin, Piotr"

Зараз показуємо 1 - 7 з 7
  • Ескіз
    Документ
    Investigation of the orientation of galaxies in clusters: the importance, methods and results of research
    (2019) Pajowska, Paulina; Godlowski, Wlodzimierz; Zhu, Zong-Hong; Popiela, Joanna; Panko, Olena O.; Flin, Piotr; Панько, Олена Олексіївна; Панько, Елена Алексеевна
    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 allows to analyze 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 how powerful is 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.
  • Ескіз
    Документ
    The Adopted Morphological Types of 247 Rich PF Galaxy Clusters
    (2016) Panko, Olena O.; Bajan, Katarzyna; Flin, Piotr; Gotsulyak, Alla; Панько, Олена Олексіївна; Панько, Елена Алексеевна
    Morphological types were determined for 247 rich galaxy clusters from the PF Catalogue of Galaxy Clusters and Groups. The adopted types are based on classical morphological schemes and consider concentration to the cluster center, the signs of preferential direction or plane in the cluster, and the positions of the brightest galaxies. It is shown that both concentration and preferential plane are significant and independent morphological criteria.
  • Ескіз
    Документ
    The Evolution of Low-Redshift Galaxy Structures
    (2009) Biernacka, Monika; Flin, Piotr; Panko, Olena O.; Панько, Олена Олексіївна; Панько, Елена Алексеевна
    Ellipticities for 6188 low-redshift (z < 0.18) poor and rich galaxy structures have been examined along with their evolution using an optical observational base that is statistically complete. The shape of each structure projected on the celestial sphere was determined using the covariance ellipse method. Analysis of the data indicates that structure ellipticity changes with redshift, being smaller for nearby objects and greater for those located further away. Such a change is also described better by quadratic or exponential relations than by a simple linear scheme. It is concluded that between redshifts of z = 0.18 and z = 0 we observe the dynamical evolution of galaxy clusters. Such a change in ellipticity with redshift is expected in ΛCDM models.
  • Ескіз
    Документ
    The Investigation of the Luminosity Function for Sample 6168 Galaxy Clusters
    (2018) Godlowski, Wlodzimierz; Popiela, Joanna; Biernacka, Monika; Bajan, Katarzyna; Panko, Olena O.; Pajowska, Paulina; Flin, Piotr; Панько, Олена Олексіївна; Панько, Елена Алексеевна
    The issue of construction of the luminosity function is an important problem for analysis of large scale structure statistics and interpretation of astronomical object counts In the present paper we discuss the the issure of the construction of the luminosity function for galaxy clusters. The problem is solved based on counting brightness of galaxies belonging to 6168 galaxy clusters selected from Panko & Flin (2006) Catalogue. We show that the galaxy clusters are characterized by the luminosity function signi cantly di erent than that obtained for both: individual optical galaxies and radiogalaxies. We discuss the signi cance of this result for the theories of the structure formation.
  • Ескіз
    Документ
    The Orientation of Galaxies in Galaxy Clusters
    (2010) Godlowski, Wlodzimierz; Pajowska, Paulina; Panko, Olena O.; Flin, Piotr; Панько, Олена Олексіївна; Панько, Елена Алексеевна
    We present an analysis of the spatial orientations of galaxies in 247 optically selected rich Abell clusters which have at least 100 members in the considered area.We investigated the relation between angles that give information about galaxy angular momenta and the number of members in each structure. The position angles of the galaxies’ major axes, as well as two angles describing the spatial orientation of the galaxy plane, were tested for isotropy by applying three different statistical tests. It is found that the values of the statistics increase with the amount of the galaxies’ members, which is equivalent to the existence of a relation between anisotropy and the number of galaxies in a cluster. The search for connection between the galaxies’ alignments and Bautz–Morgan (BM) morphological types of examined clusters showed a weak dependence. A statistically marginal relation between velocity dispersion and cluster richness was observed. In addition, it was found that the velocity dispersion decreases with BM type at almost 3σ level. These results show the dependence of alignments with respect to clusters’ richness, which can be regarded as an environmental effect.
  • Ескіз
    Документ
    The Properties of Nearby Galaxy Structures
    (2009) Biernacka, Monika; Flin, Piotr; Juszczyk, T.; Panko, Olena O.; Панько, Олена Олексіївна; Панько, Елена Алексеевна
    We constructed the statistically uniform catalogue of 6188 galaxy structures, having at least 10 members in the structure field. These structures were extracted through the application of the Voronoi tessellation to Muenster Red Sky Survey which is a catalogue of galaxies based on scans of 217 ESO plates in the region covering about 5000 square degrees. We found that the shape of structures projected on the celestial sphere is different for rich and poor structures, which can reflect condition during their formation. Recent (for z < 0.18) weak dynamical evolution of galaxy clusters is observed. The distributions of position angles of ten brightest galaxies in structure are isotropic. The position angle of the brightest cluster member tend to be align with the parent cluster major axis only in the case of BM type I clusters, this is clusters containing cD galaxy.
  • Ескіз
    Документ
    The Shape of Galaxy Structures
    (The Astrophysical Journal, 2009) Panko, Olena O.; Juszczyk, Teresa; Biernacka, Monika; Flin, Piotr; Панько, Олена Олексіївна; Панько, Елена Алексеевна
    An analysis is presented for a statistically complete sample of 547 galaxy structures with z 0.16, each containing at least 10 objects. The sample was divided according to structure richness, representing 10 richness classes, with the distribution of ellipticities differing among individual classes. Mean ellipticity varies from 0.34 to 0.18, less well populated structures being more elongated that richer ones. Statistics indicate that structures with at least 50 members originate from the same population. The mean redshift of a structure class is a function of richness, with less well populated classes exhibiting greater mean redshifts than richer galaxy clusters. Further analysis reveals a dependence of the ellipticity-redshift correlation on structure richness. Among rich galaxy clusters there is an anticorrelation between the parameters, the strongest correlation occurring for the most poorly populated galaxy classes.