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 Laniakea Supercluster, created using Mandelbulb, a 3D fractal software by Calder Moore (https://www.artstation.com/artwork/laniakea-supercluster) |
As an observational astronomer, I have been studying the formation and evolution of the large-scale structure of the Universe and its building blocks. For my studies, I either use massive astronomical archival data from ground- and space-based telescopes, or I make my own observations. Any data-dependent research can no longer be a one-man’s job in modern science. The overwhelming amount of astronomical data demands team effort. Observational Astronomy is heavily built upon query-based data acquisition, noise reduction, pipeline design, archive management, data mining, algorithm design, and parallel programming only to perform measurements prior to testing and constraining theoretical models.
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Cosmicflows: Recovering the Structure and Dynamics of the Local Universe
To explore the Large Scale Structures of the Universe, precise 3-dimensional information on the spatial distribution of galaxies and their velocities is required. There are several methods to measure the line-of-sight distance of a galaxy. The uncertainties on distance measurement depends on the applied method and it increases with distance. On the other hand, the measured radial velocity of galaxies are deviated from the global Hubble expansion due to the local gravitational instabilities. In the Local Universe, the contribution of the cosmic expansion is usually large compared to peculiar velocity of galaxies. Therefore, it is important to increase the spatial number density and homogeneity of the cataloged galaxies with measured distances to improve the peculiar velocity measurements. In this study, our focus is on the correlation between rotation rate and absolute luminosity of the spiral galaxies, known as Tully-Fisher Relation (TFR). In this project, I am compiling the next generation of Cosmicflows distances (Cosmicflows-4) that consists of ~35,000 galaxies with accurately measured distances. This is the most complete distance catalog of galaxies by far. Then with the aid of our team members, I am using this catalog to measure the local flows of local galaxies, using which we are carefully mapping the underlying structures, like voids and over-dense structures. Providing such a high quality big catalog of galaxy distances increases the resolution of all previous maps, with covering more regions for which we did not have any previous data, and it extends our maps far beyond any other studies so far. This ambitious project tries to deepen our vision to our local Universe far beyond our home supercluster: Laniakea. Surprisingly, regarding the visualization products of this project (videos, maps and graphs), there is only minor differentiation between what we publish in scientific journals and what is created for public consumptions.
To explore the Large Scale Structures of the Universe, precise 3-dimensional information on the spatial distribution of galaxies and their velocities is required. There are several methods to measure the line-of-sight distance of a galaxy. The uncertainties on distance measurement depends on the applied method and it increases with distance. On the other hand, the measured radial velocity of galaxies are deviated from the global Hubble expansion due to the local gravitational instabilities. In the Local Universe, the contribution of the cosmic expansion is usually large compared to peculiar velocity of galaxies. Therefore, it is important to increase the spatial number density and homogeneity of the cataloged galaxies with measured distances to improve the peculiar velocity measurements. In this study, our focus is on the correlation between rotation rate and absolute luminosity of the spiral galaxies, known as Tully-Fisher Relation (TFR). In this project, I am compiling the next generation of Cosmicflows distances (Cosmicflows-4) that consists of ~35,000 galaxies with accurately measured distances. This is the most complete distance catalog of galaxies by far. Then with the aid of our team members, I am using this catalog to measure the local flows of local galaxies, using which we are carefully mapping the underlying structures, like voids and over-dense structures. Providing such a high quality big catalog of galaxy distances increases the resolution of all previous maps, with covering more regions for which we did not have any previous data, and it extends our maps far beyond any other studies so far. This ambitious project tries to deepen our vision to our local Universe far beyond our home supercluster: Laniakea. Surprisingly, regarding the visualization products of this project (videos, maps and graphs), there is only minor differentiation between what we publish in scientific journals and what is created for public consumptions.
Cosmicflows-3 Distance–Velocity Calculator
Smart Evaluation of Spirals Inclinations with Convolutional Neural Network
An application to automatically find the the spatial inclination of Spiral Galaxies using Convolutional Neural Network. The model has been implemented in TensorFlow and uses the outputs of the Galaxy Inclination Zoo for ~10,000 spirals.
Galaxy Inclination Zoo (Inclination Participative Project)
This is part of the Cosmicflows4 project to measure the distance of ~20,000 local spiral galaxies. This is a collaborative project that allows everyone interested in science to participate. The goal of this project is to find the inclination of these galaxies relative to the known standard galaxies. To achieve this goal, we offer a GUI to visually inspect these galaxies and to insert them between the standard galaxies.
Overview
The main objective of this program is to measure the inclination of a set spiral galaxies by comparing them with a number of standard galaxies. At each step, there is only one target galaxy which is displayed in a yellow panel. The inclinations of the other galaxies are known. All the standard galaxies are ordered based on their inclinations from left to right, with left galaxies having lower inclinations. User can only move the target galaxy using either the controlling left/right arrow buttons, or other methods, e.g. dragging the target panel from the middle row and replace it, or using 'A' and 'D' keys on keyboard.
To estimate the inclination of each galaxy, user goes through two steps at most. In step A, the difference in the inclination of standard galaxies is 5 degrees. Once user narrows down the approximate location of the galaxy, (s)he has the chance to increase the measurement accuracy in step B, where the inclinations are 1 degree apart. Therefore, at the end we expect users to estimate the inclination of an unknown galaxy with the accuracy of ~1 degree. Inclinations smaller than 45 degrees (i.e. galaxies more face-on than 45 degrees) would be rejected and flagged automatically and they would not be used for the distance measurement analysis.
The main objective of this program is to measure the inclination of a set spiral galaxies by comparing them with a number of standard galaxies. At each step, there is only one target galaxy which is displayed in a yellow panel. The inclinations of the other galaxies are known. All the standard galaxies are ordered based on their inclinations from left to right, with left galaxies having lower inclinations. User can only move the target galaxy using either the controlling left/right arrow buttons, or other methods, e.g. dragging the target panel from the middle row and replace it, or using 'A' and 'D' keys on keyboard.
To estimate the inclination of each galaxy, user goes through two steps at most. In step A, the difference in the inclination of standard galaxies is 5 degrees. Once user narrows down the approximate location of the galaxy, (s)he has the chance to increase the measurement accuracy in step B, where the inclinations are 1 degree apart. Therefore, at the end we expect users to estimate the inclination of an unknown galaxy with the accuracy of ~1 degree. Inclinations smaller than 45 degrees (i.e. galaxies more face-on than 45 degrees) would be rejected and flagged automatically and they would not be used for the distance measurement analysis.
Laniakea: Our Home Supercluster |
The Dipole Repeller
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The Milky Way is moving through space because of hidden void
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