Research
AGNs Classification - SDSS Dr18
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Topic: Classification of Emission Line Galaxies out of 30,000
galaxies sample with an average z ≈ 0.08 from SDSS Dr18 Team Dr. Harjeet Kaur (Nuclear Physicist) (Department of Physics, Guru Nanak Dev University) Date: August 11, 2023 - Present |
Email for academic inquiries: |
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My work involves classification of strong emision line spectrum galaxies - Emission Line Galaxies (ELGs). The strong emission lines indicate the presence of very hot
gas, leading to ionisation of the elements. There could be different sources that heat this gas - from active star
formation to massive young stars to an accreting black hole.
The data used in this work were taken from the Sloan Digital Sky Survey (SDSS) Data Release 18 (DR18) (Almeida et al. 2023). The survey uses the 2.5m telescope facility in the Apache Point Observatory, USA. DR18 is the first data release of its fifth phase, which aims to perform optical and infra-red spectroscopy of the entire sky. In this report, I looked at some of the classification schemes and diagnostic tools for Emission Line Galaxies. Each classification tries to overcome the limitations of the other. As these classifications capture different physical processes, ‘misclassifications’ between them could lead to interesting observations as in the case of SDSS J125305.97-031258.8. The ultimate goal of such explorations is faster and reliable classification pipelines that could help understand the physics of the respective population classes. |
It is observed that increasing number of objects are classified as AGNs with decreasing wavelength (2b,2a,2c). Instead of comparing with the ‘class’ provided by SDSS, if we group subclasses we have a higher percentage of QSO ≈ 7.6%. This value is close to the values we obtain from BPT.
My sample consists of 30,000 galaxies with narrow lines (FW HM < 500km/s, S/N > 5) and redshift z < 0.3 with
an average z ≈ 0.08.
Image: BPT diagram and Table from my research paper |
Star Formation Rate Correlation with the Mass of Galaxies and their Metallicity
My research pertain to a study on the correlation between the star
formation rate (SFR) and the mass and metallicity of galaxies.
The research method involved the collection and analysis of data from the Sloan Digital Sky Survey Data Release 7 (SDSS DR7). The data contained information on the star formation rate (SFR), mass, and metallicity of galaxies.
The research finding where shared in astronomy event at PEC, astronomy club and with teachers.
Research Poster: pdf file
The research method involved the collection and analysis of data from the Sloan Digital Sky Survey Data Release 7 (SDSS DR7). The data contained information on the star formation rate (SFR), mass, and metallicity of galaxies.
The research finding where shared in astronomy event at PEC, astronomy club and with teachers.
Research Poster: pdf file
SDSS3: Type Ia Supernovae redshift ≤ 0.5 analysis on the basis of
there respective distances
In this project, I present the prediction for Type Ia supernovae on
the basis of their distances. I compared recessional velocity (is the rate at
which an extragalactic astronomical object recedes from an
observer as a result of the expansion of the universe. The
product of redshift and speed of light gives us the same) to
the distance from the supernova. My main working tool was Python.