Dissecting Distant Galaxies Using Normalized High-Redshift Quasar Spectra
School Name
South Carolina Governor's School for Science and Mathematics
Grade Level
12th Grade
Presentation Topic
Physics
Presentation Type
Mentored
Abstract
Quasar-absorber systems are integral to the study of distant objects that are too dim to be observed on their own. These objects, distant in both space and time, tell us the story of the early universe, including the evolution of galaxies. Using quasars as backlights, we can analyze the composition of faraway galaxies via their spectra. This project analyzed spectra taken by the VLT in Chile by normalizing them in the program Linetools. This required the calculation of both the quasar and the galaxy’s redshifts, as well as the manual fitting of the continuum. Once the spectrum was normalized, effectively removing the quasar’s emission lines, the absorption lines of the galaxy were measured using equivalent width and column density. These measurements were used to calculate metallicity, which revealed that the galaxy is very young due to its low quantity of metals. However, the presence of FeII indicated Type II supernovas, proving that it has existed through the lifetimes of some stars within it. Both the redshift and the presence of highly ionized metals indicated that the galaxy is very near the quasar. Ultimately, this galaxy is a piece in the much larger puzzle that is the study of quasar-absorber systems, and each analysis of such a system brings us one step closer to revealing the greater picture of the evolution of the universe around us.
Recommended Citation
Vaneman, Taliesin, "Dissecting Distant Galaxies Using Normalized High-Redshift Quasar Spectra" (2023). South Carolina Junior Academy of Science. 103.
https://scholarexchange.furman.edu/scjas/2023/all/103
Location
ECL 114
Start Date
3-25-2023 9:00 AM
Presentation Format
Oral Only
Group Project
No
Dissecting Distant Galaxies Using Normalized High-Redshift Quasar Spectra
ECL 114
Quasar-absorber systems are integral to the study of distant objects that are too dim to be observed on their own. These objects, distant in both space and time, tell us the story of the early universe, including the evolution of galaxies. Using quasars as backlights, we can analyze the composition of faraway galaxies via their spectra. This project analyzed spectra taken by the VLT in Chile by normalizing them in the program Linetools. This required the calculation of both the quasar and the galaxy’s redshifts, as well as the manual fitting of the continuum. Once the spectrum was normalized, effectively removing the quasar’s emission lines, the absorption lines of the galaxy were measured using equivalent width and column density. These measurements were used to calculate metallicity, which revealed that the galaxy is very young due to its low quantity of metals. However, the presence of FeII indicated Type II supernovas, proving that it has existed through the lifetimes of some stars within it. Both the redshift and the presence of highly ionized metals indicated that the galaxy is very near the quasar. Ultimately, this galaxy is a piece in the much larger puzzle that is the study of quasar-absorber systems, and each analysis of such a system brings us one step closer to revealing the greater picture of the evolution of the universe around us.
