scholarly journals Spatial Orientations of Angular Momentum Vectors of Galaxies in Supercluster S [195+027+0022] and Substructure

2021 ◽  
Vol 7 (2) ◽  
pp. 81-88
Author(s):  
J. R. Malla ◽  
W. Saurer ◽  
B. Aryal
Keyword(s):  
Galaxy Evolution ◽  
Azimuthal Angle ◽  
Three Dimensional ◽  
Simulation Method ◽  
Position Angle ◽  
Sloan Digital Sky Survey ◽  
Chi Square ◽  
Rotation Axes ◽  
Sky Survey ◽  
The Galaxy

This paper presents an analysis of the spin vector orientations of SDSS (Sloan Digital Sky Survey) galaxies in the Supercluster S [195+027+0022] using the seventh data release (2008 October). By using the spectroscopic database of galaxies, identified number density map in the region of Superclusters. Several density enhancements are observed, suggesting the possibility of substructure in the Supercluster. Two-dimensional observed parameters that we received from the database are used to compute three-dimensional galaxy rotation axes by applying `position angle-inclination' method. Apply the selection effects by performing the random simulation method. The expected distribution curves are obtained from the simulation. Chi-square, auto-correlation, and Fourier tests are used to examine non-random effects in the polar and azimuthal angle distributions of the galaxy rotation axes. To check these results with the different galaxy evolution models namely Hierarchy, Primordial, and Pancake model. The result supports the Hierarchy model.

scholarly journals Variation of Spatial Orientation with Increase in Red Shift

2018 ◽  
Vol 6 ◽  
pp. 43-46
Author(s):  
Ranjit Prasad Yadav
Keyword(s):  
Statistical Tests ◽  
Random Effect ◽  
Azimuthal Angle ◽  
Position Angle ◽  
Red Shift ◽  
Chi Square ◽  
Rotation Axes ◽  
Isotropic Distribution ◽  
Sky Survey ◽  
The Galaxy

The main aim of this article is to analyze non-random effect s in galaxy orientation. The result is based on the analysis of the spatial orientations of SDSS (Soloan Digital Sky Survey) galaxies of red shift 0.10000 to 0.1001 (radial velocity: 30000km/s to30030km/) using seventh data released in October 2008. The position angle inclination method is used to find the polar and azimuthal angles of galaxy rotation axes. To analyze the distribution of the polar and azimuthal angle of the galaxy rotation axes and to check for an isotropy or anisotropy the three statistical tests have carried out: chi- square, Fourier and auto correlation. It was done assuming the spatially isotropic distribution to examine non-random effects. It was found that the spin vector orientations of the galaxies in the sample Z1 and Z2 are almost isotropic.Academic Voices Vol.6 2016: 43-46

scholarly journals A Study of R-Magnitude Dependence in Spatial Orientation of Spin Vectors of SDSS DR-7 Galaxies of Redshift 0.10 < Z < 0.11

2020 ◽  
Vol 13 (13) ◽  
pp. 42-45
Author(s):  
Shiv Narayan Yadav
Keyword(s):  
Galaxy Formation ◽  
Spatial Orientation ◽  
Three Dimensional ◽  
Simulation Method ◽  
Sloan Digital Sky Survey ◽  
Spin Vector ◽  
Local Anisotropy ◽  
Charge Coupled Device ◽  
Rotation Axes ◽  
Sky Survey

We present a study of spin vector orientations of 44749 r-magnitude SDSS (Sloan Digital Sky Survey) galaxies having redshift 0.10 to 0.11. The r -magnitudes are observed through 616.5 nm CCD (charge coupled device) filter attached to SDSS telescope located at New Mexico, USA. We have converted two dimensional data to three dimensional galaxy rotation axes. Our aim is to find out non-random effects in the spatial orientation of galaxies. In addition, we wanted to check r-magnitude dependence in the spatial orientation. The expected isotropy distribution curves are obtained by removing the selection effects and performing a random simulation method. In general, spin vector orientations of galaxies is found to be random, supporting Hierarchy model of galaxy formation. A local anisotropy is observed in few samples suggesting a gravitational tidal interaction between neighbor galaxies.

scholarly journals Spatial orientations of angular momentum vectors of galaxies in Supercluster S [173+014+0082]

BIBECHANA ◽  
2021 ◽  
Vol 18 (1) ◽  
pp. 26-32
Author(s):  
Janak Ratna Malla ◽  
Walter Saurer ◽  
B Aryal
Keyword(s):  
Angular Momentum ◽  
Galaxy Formation ◽  
Three Dimensional ◽  
Position Angle ◽  
Sloan Digital Sky Survey ◽  
Chi Square ◽  
Isotropic Distribution ◽  
The Galaxy ◽  
Inclination Angles ◽  
Chi Square Test

The spin vector orientation of 1302 SDSS (Sloan Digital Sky Survey) galaxies in Supercluster S[173+014+0082] having redshift 0.076 to 0.091 has been analysed. The positions, position angles and inclination angles of galaxies are used to convert two-dimensional observed parameters into three-dimensional angular momentum vectors of the galaxy using the `position angle-inclination' method. The expected isotropic distribution curves are determined performing numerical simulation by generating 107 virtual galaxies. The observed distribution is compared with the expected isotropic distribution curves using three statistical tools namely Chi-square test, auto-correlation test and Fourier test. Redshift map is studied and found that the distributions fit with the Gaussian. No preferred alignment of angular momentum vectors is noticed, supporting Hierarchy model of galaxy formation. BIBECHANA 18 (2021) 26-32  

scholarly journals Surface Photometry of Spiral Galaxy NGC 5005 and Elliptical Galaxy NGC 4278

2018 ◽  
Vol 15 (3) ◽  
pp. 314-323
Author(s):  
Baghdad Science Journal
Keyword(s):  
Spiral Galaxy ◽  
Surface Brightness ◽  
Elliptical Galaxy ◽  
Position Angle ◽  
Sloan Digital Sky Survey ◽  
Surface Photometry ◽  
Contour Maps ◽  
Sky Survey ◽  
Flat Field ◽  
The Galaxy

Two galaxies have been chosen, spiral galaxy NGC 5005 and elliptical galaxy NGC 4278 to study their photometric properties by using surface photometric techniques with griz-Filters. Observations are obtained from the Sloan Digital Sky Survey (SDSS). The data reduction of all images have done, like bias and flat field, by SDSS pipeline. The overall structure of the two galaxies (a bulge, a disk), together with isophotal contour maps, surface brightness profiles and a bulge/disk decomposition of the galaxy images were performed, although the disk position angle, ellipticity and inclination of the galaxies have been estimated.

scholarly journals Spatial Orientation of Galaxies in Supercluster S[195+027+0022]

2019 ◽  
Vol 5 (1) ◽  
pp. 14-18
Author(s):  
J. R. Malla ◽  
B. Aryal ◽  
W. Saurer
Keyword(s):  
Galaxy Formation ◽  
Spatial Orientation ◽  
Three Dimensional ◽  
Position Angle ◽  
Sloan Digital Sky Survey ◽  
Spin Vector ◽  
Sky Survey ◽  
Hierarchy Model ◽  
Vector Orientation ◽  
Angle Method

We present a study of spin vector orientation of 1198 SDSS (Sloan Digital Sky Survey) galaxies in Super cluster S[195+027+0022] having red shift 0.07 to 0.09. The databases of these galaxies are taken from SDSS (Sloan Digital Sky Survey) 7th and 9th data release. We have converted two dimensional data to three-dimensional by Godlowskian Transformation using position angle-inclination angle method. We intend to find non-random effects in the spatial orientation of galaxies in Super cluster. No preferred alignment of angular momentum vectors (spin vector) is noticed, supporting Hierarchy model of galaxy formation.

scholarly journals A Study of r- and u-Magnitude Dependence in the Spatial Orientation of Spin Vectors of SDSS Galaxies having redshift 0.10 < z < 0.11

2015 ◽  
Vol 5 ◽  
pp. 1-11
Author(s):  
Shiv Narayan Yadav ◽  
Binil Aryal
Keyword(s):  
Galaxy Formation ◽  
Spatial Orientation ◽  
Three Dimensional ◽  
Simulation Method ◽  
Sloan Digital Sky Survey ◽  
Angular Momentum Vector ◽  
Spin Vector ◽  
Local Anisotropy ◽  
Rotation Axes ◽  
Merging Process

We present a study of spin vector orientations of 44749 r and u-magnitude SDSS (Sloan Digital Sky Survey) galaxies having redshift 0.10 to 0.11. The r and u-magnitudes are observed through 616.5 nm and 354.3 nm CCD (charge coupled device) filter attached to SDSS telescope located at New Mexico, USA. We have converted two dimensional data to three dimensional galaxy rotation axes. Our aim is to find out non-random effects in the spatial orientation of galaxies. In addition, we wanted to check r and u-magnitude dependence in the spatial orientation. The expected isotropy distribution curves are obtained by removing the selection effects and performing a random simulation method. In general, spin vector orientations of galaxies is found to be random, supporting Hierarchy model of galaxy formation. A local anisotropy is observed in few samples suggesting a gravitational tidal interaction between neighbor galaxies, a merging process in which the angular momentum vector distort the original alignment of evolution of rotational supported system to the randomized system.The Himalayan Physics Year 5, Vol. 5, Kartik 2071 (Nov 2014)Page: 1-11

Classification and Characterization of Objects from the Galaxy Evolution Explorer Survey and the Sloan Digital Sky Survey

2005 ◽  
Vol 619 (1) ◽  
pp. L27-L30 ◽  
Author(s):  
Luciana Bianchi ◽  
Mark Seibert ◽  
Wei Zheng ◽  
David A. Thilker ◽  
Peter G. Friedman ◽  
...  
Keyword(s):  
Galaxy Evolution ◽  
Sloan Digital Sky Survey ◽  
Sky Survey ◽  
The Galaxy

scholarly journals A Zoo of Galaxies

2012 ◽  
Vol 10 (H16) ◽  
pp. 1-15
Author(s):  
Karen L. Masters
Keyword(s):  
Galaxy Evolution ◽  
Sloan Digital Sky Survey ◽  
Historical Background ◽  
The Public ◽  
Astronomical Surveys ◽  
Sky Survey ◽  
The Galaxy ◽  
Scientific Papers ◽  
Galaxy Classification

AbstractWe live in a universe filled with galaxies with an amazing variety of sizes and shapes. One of the biggest challenges for astronomers working in this field is to understand how all these types relate to each other in the background of an expanding universe. Modern astronomical surveys (like the Sloan Digital Sky Survey) have revolutionised this field of astronomy, by providing vast numbers of galaxies to study. The sheer size of the these databases made traditional visual classification of the types galaxies impossible and in 2007 inspired the Galaxy Zoo project (www.galaxyzoo.org); starting the largest ever scientific collaboration by asking members of the public to help classify galaxies by type and shape. Galaxy Zoo has since shown itself, in a series of now more than 30 scientific papers, to be a fantastic database for the study of galaxy evolution. In this Invited Discourse I spoke a little about the historical background of our understanding of what galaxies are, of galaxy classification, about our modern view of galaxies in the era of large surveys. I finish with showcasing some of the contributions galaxy classifications from the Galaxy Zoo project are making to our understanding of galaxy evolution.

scholarly journals Detecting multi-scale filaments in galaxy distribution

2014 ◽  
Vol 10 (S306) ◽  
pp. 45-47
Author(s):  
Elmo Tempel
Keyword(s):  
Point Process ◽  
Large Scale ◽  
Three Dimensional ◽  
Sloan Digital Sky Survey ◽  
Point Distribution ◽  
Multi Scale ◽  
Galaxy Distribution ◽  
Sky Survey ◽  
The Galaxy ◽  
Redshift Survey

AbstractThe main feature of the spatial large-scale galaxy distribution is its intricate network of galaxy filaments. This network is spanned by the galaxy locations that can be interpreted as a three-dimensional point distribution. The global properties of the point process can be measured by different statistical methods, which, however, do not describe directly the structure elements. The morphology of the large-scale structure, on the other hand, is an important property of the galaxy distribution. Here, we apply an object point process with interactions (the Bisous model) to trace and extract the filamentary network in the presently largest galaxy redshift survey, the Sloan Digital Sky Survey (SDSS data release 10). We search for multi-scale filaments in the galaxy distribution that have a radius of about 0.5, 1.0, 2.0, and 4.0h−1Mpc. We extract the spines of the filamentary network and divide the detected network into single filaments.

scholarly journals A Study of co-existence between the Hubble flow and the random alignments of spin vectors of SDSS galaxies

BIBECHANA ◽  
2014 ◽  
Vol 12 ◽  
pp. 114-127
Author(s):  
Shiv Narayan Yadav ◽  
Walter Saurer ◽  
Binil Aryal
Keyword(s):  
Coordinate System ◽  
Galaxy Evolution ◽  
Spatial Orientation ◽  
Particle Physics ◽  
Large Scale ◽  
Statistical Tests ◽  
Azimuthal Angle ◽  
Three Dimensional ◽  
Simulation Method ◽  
Hubble Flow

We present a study of spin vector orientation of 14,118 SDSS (Sloan Digital Sky Survey) galaxies having redshift in the range 0.19 to 0.20 (radial velocity 57,000 km/s to 60,000 km/s) with respect to galactic coordinate system using 7th data release (2008, October). These galaxies were observed through SDSS telescope of Apache Point Observatory located at New Mexico, USA. The photometric database is made available through our collaboration with institute of Astro-particle physics, Innsbruck University, Austria. We used the `Godlowskian' method to convert two dimensional data to three dimensional galaxy rotation axes. Our intension is to find out non-random effects in the spatial orientation of galaxies and to check  redshift dependence. The expected isotropy distribution curves are obtained by removing the selection effects and performing a random simulation method. The observed and expected polar and azimuthal angle distributions are compared by using three statistical tests- chi-square, auto-correlation and the Fourier. It is found that the spatial orientation of galaxies tend to be oriented randomly with respect to the galactic coordinate system, supporting hierarchy model of galaxy evolution. In few cases we noticed a preference, probably due to the gravitational shearing or tidal effects in the large scale structure. In general, redshift is found to be independent of orientation. Hence, a very good correlation between the Hubble flow (redshift) and the random alignments of spin vectors of SDSS galaxies is noticed.DOI: http://dx.doi.org/10.3126/bibechana.v12i0.11787BIBECHANA 12 (2015) 114-127

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