mahdi khadem ferdowsi university of mashhad. large-scale structures there are various structures in...
TRANSCRIPT
![Page 1: Mahdi Khadem Ferdowsi University of Mashhad. Large-scale structures There are various structures in the Universe: Groups and Clusters Walls and filaments](https://reader036.vdocuments.us/reader036/viewer/2022062409/5697bf811a28abf838c8518b/html5/thumbnails/1.jpg)
Mahdi KhademFerdowsi University of Mashhad
![Page 2: Mahdi Khadem Ferdowsi University of Mashhad. Large-scale structures There are various structures in the Universe: Groups and Clusters Walls and filaments](https://reader036.vdocuments.us/reader036/viewer/2022062409/5697bf811a28abf838c8518b/html5/thumbnails/2.jpg)
Large-scale structuresThere are various structures in the
Universe:Groups and ClustersWalls and filamentsVoids
SDSS data and the CfA2 catalog →
![Page 3: Mahdi Khadem Ferdowsi University of Mashhad. Large-scale structures There are various structures in the Universe: Groups and Clusters Walls and filaments](https://reader036.vdocuments.us/reader036/viewer/2022062409/5697bf811a28abf838c8518b/html5/thumbnails/3.jpg)
VoidsThere is not a standard definition for “void”
in cosmology.Weygaret and Kampen (1993):
Irregular low-density regions in the density fieldEl-Ad and Piran (1997)
Continues volumes that do not contain any wall galaxies.
…
![Page 4: Mahdi Khadem Ferdowsi University of Mashhad. Large-scale structures There are various structures in the Universe: Groups and Clusters Walls and filaments](https://reader036.vdocuments.us/reader036/viewer/2022062409/5697bf811a28abf838c8518b/html5/thumbnails/4.jpg)
Our definition:Irregular regions in the density field that their
density is less than 20% of average density in each redshift.
Voids
![Page 5: Mahdi Khadem Ferdowsi University of Mashhad. Large-scale structures There are various structures in the Universe: Groups and Clusters Walls and filaments](https://reader036.vdocuments.us/reader036/viewer/2022062409/5697bf811a28abf838c8518b/html5/thumbnails/5.jpg)
COSMOS Data BaseCOMOS released latest galactic data in fall
2008.It contains 304999 galaxies between
zph=0.01 to zph=5.00.I selected all galaxies which have zph less
than 3.00.This release has accuracy of 0.001 in
redshift.
![Page 6: Mahdi Khadem Ferdowsi University of Mashhad. Large-scale structures There are various structures in the Universe: Groups and Clusters Walls and filaments](https://reader036.vdocuments.us/reader036/viewer/2022062409/5697bf811a28abf838c8518b/html5/thumbnails/6.jpg)
Void Finding ProcessCalculating comoving distance and galactic
longitude and latitude for all galaxies.Making cylindrical sample
I made various cylindrical samples with 5, 10, 15 and 20 Mpc diameter.
Sample Diameter
![Page 7: Mahdi Khadem Ferdowsi University of Mashhad. Large-scale structures There are various structures in the Universe: Groups and Clusters Walls and filaments](https://reader036.vdocuments.us/reader036/viewer/2022062409/5697bf811a28abf838c8518b/html5/thumbnails/7.jpg)
Dividing cylindrical sample to cells
Calculating galactic number density in each cell in order to find voids
Void Finding Process
Cells length: 5 Mpc
![Page 8: Mahdi Khadem Ferdowsi University of Mashhad. Large-scale structures There are various structures in the Universe: Groups and Clusters Walls and filaments](https://reader036.vdocuments.us/reader036/viewer/2022062409/5697bf811a28abf838c8518b/html5/thumbnails/8.jpg)
Void Finding ProcessCalculating mean distance and galactic
number density by redshift
D= 10 Mpc
![Page 9: Mahdi Khadem Ferdowsi University of Mashhad. Large-scale structures There are various structures in the Universe: Groups and Clusters Walls and filaments](https://reader036.vdocuments.us/reader036/viewer/2022062409/5697bf811a28abf838c8518b/html5/thumbnails/9.jpg)
Void Finding Process
D=5 Mpc
Calculating mean distance and galactic number density by redshift
![Page 10: Mahdi Khadem Ferdowsi University of Mashhad. Large-scale structures There are various structures in the Universe: Groups and Clusters Walls and filaments](https://reader036.vdocuments.us/reader036/viewer/2022062409/5697bf811a28abf838c8518b/html5/thumbnails/10.jpg)
![Page 11: Mahdi Khadem Ferdowsi University of Mashhad. Large-scale structures There are various structures in the Universe: Groups and Clusters Walls and filaments](https://reader036.vdocuments.us/reader036/viewer/2022062409/5697bf811a28abf838c8518b/html5/thumbnails/11.jpg)
Thanks For Attention