Insights into Quiescent Galaxies and Their Evolution
Research on quiet galaxies reveals key aspects of their formation and evolution.
― 4 min read
Table of Contents
- Methods of Observing
- Observing Quiescent Galaxies
- Results from Surveys
- Number Density of Quiescent Galaxies
- Variation Among Fields
- Visual Inspection and Data Quality
- Stellar Masses and Growth
- The Role of Cosmic Dust
- Comparison with Previous Studies
- Implications for Future Research
- Conclusion
- Original Source
- Reference Links
The study of galaxies helps us learn more about how they form and change over time. In particular, scientists are interested in quiet galaxies, which are those that have stopped forming new stars. Observing these galaxies, especially those that are far away, is vital to understand how galaxies evolve in the early universe.
Methods of Observing
Researchers use advanced telescopes equipped with different filters to capture images of galaxies. The James Webb Space Telescope (JWST) is one of the best tools we have for this purpose. It can see light that is not visible to the naked eye and can capture images at different wavelengths. This makes it easier to collect data on various types of galaxies at different stages of their life cycles.
Observing Quiescent Galaxies
Quiescent galaxies are characterized by their low star formation rates. These galaxies become less active over time, and understanding the reasons behind this can give insights into the overall process of galaxy formation and evolution.
Researchers use specific methods to select and study these galaxies. They apply certain criteria to identify them among many others that still form stars. Traditional methods rely on color and brightness measurements, while newer techniques involve complex modeling approaches.
Results from Surveys
Recent observations have focused on several fields in the universe to gather data on quiescent galaxies. These studies have revealed previously unknown information about how these galaxies behave over time, their distribution across various environments, and their relationship with star formation.
Number Density of Quiescent Galaxies
The term "number density" refers to how many quiescent galaxies exist in a specific volume of space. This metric is crucial as it can help researchers understand how galaxy populations change and grow over time. By collecting data in specific areas of the sky, researchers can estimate how many quiescent galaxies are present in different cosmic epochs.
Variation Among Fields
Different observation fields often yield varying results. Some fields might show a high number of quiescent galaxies, while others have fewer. This variation can be attributed to cosmic variance-a natural fluctuation in the distribution of galaxies across the universe. Massive galaxies might cluster together, indicating areas with increased density compared to more sparse regions.
Visual Inspection and Data Quality
Following the initial identification of potential quiescent galaxies, researchers often conduct visual inspections to ensure the quality of the data. This involves checking images and data fits to confirm the selection is reliable. Clear, high-quality images are crucial to avoid including galaxies that may not fit the defined criteria.
Stellar Masses and Growth
The mass of a galaxy is an important factor in its evolution. Quiescent galaxies tend to be more massive than star-forming ones. Observations show that the stellar mass function-a measure of the distribution of mass in galaxies-changes over time. Understanding this is vital for forming a complete picture of galaxy evolution.
The Role of Cosmic Dust
Cosmic dust affects the light we receive from galaxies. It can obscure certain wavelengths, which may lead to miscalculations of a galaxy's properties. Researchers take steps to account for dust when analyzing their data, ensuring that the measurements are as accurate as possible.
Comparison with Previous Studies
By comparing current findings with older studies, researchers can gauge progress in understanding quiescent galaxies. Previous observations provided a baseline, and newer data allows for a more refined grasp of how galaxy populations have evolved.
Implications for Future Research
Continued observation of quiescent galaxies can help scientists answer many pressing questions about galaxy formation and evolution. As more data becomes available, especially with newer telescopes and instruments, the understanding of these galaxies will become clearer. This knowledge can inform the study of the universe and its history in profound ways.
Conclusion
The study of quiescent galaxies presents an exciting opportunity to learn about the evolution of galaxies in the universe. Advanced telescopes and refined Observational Methods enable researchers to gather data that offers valuable insights into how galaxies grow, change, and interact over cosmic timescales. Continued research in this area is essential for building a comprehensive understanding of our universe.
Title: An Atlas of Color-selected Quiescent Galaxies at $z>3$ in Public $JWST$ Fields
Abstract: We present the results of a systematic search for candidate quiescent galaxies in the distant Universe in eleven $JWST$ fields with publicly available observations collected during the first three months of operations and covering an effective sky area of $\sim145$ arcmin$^2$. We homogeneously reduce the new $JWST$ data and combine them with existing observations from the $Hubble\,Space\,Telescope$. We select a robust sample of $\sim80$ candidate quiescent and quenching galaxies at $3 < z < 5$ using two methods: (1) based on their rest-frame $UVJ$ colors, and (2) a novel quantitative approach based on Gaussian Mixture Modeling of the $NUV-U$, $U-V$, and $V-J$ rest-frame color space, which is more sensitive to recently quenched objects. We measure comoving number densities of massive ($M_\star\geq 10^{10.6} M_\odot$) quiescent galaxies consistent with previous estimates relying on ground-based observations, after homogenizing the results in the literature with our mass and redshift intervals. However, we find significant field-to-field variations of the number densities up to a factor of $2-3$, highlighting the effect of cosmic variance and suggesting the presence of overdensities of red quiescent galaxies at $z>3$, as it could be expected for highly clustered massive systems. Importantly, $JWST$ enables the robust identification of quenching/quiescent galaxy candidates at lower masses and higher redshifts than before, challenging standard formation scenarios. All data products, including the literature compilation, are made publicly available.
Authors: Francesco Valentino, Gabriel Brammer, Katriona M. L. Gould, Vasily Kokorev, Seiji Fujimoto, Christian Kragh Jespersen, Aswin P. Vijayan, John R. Weaver, Kei Ito, Masayuki Tanaka, Olivier Ilbert, Georgios E. Magdis, Katherine E. Whitaker, Andreas L. Faisst, Anna Gallazzi, Steven Gillman, Clara Gimenez-Arteaga, Carlos Gomez-Guijarro, Mariko Kubo, Kasper E. Heintz, Michaela Hirschmann, Pascal Oesch, Masato Onodera, Francesca Rizzo, Minju Lee, Victoria Strait, Sune Toft
Last Update: 2023-02-21 00:00:00
Language: English
Source URL: https://arxiv.org/abs/2302.10936
Source PDF: https://arxiv.org/pdf/2302.10936
Licence: https://creativecommons.org/licenses/by/4.0/
Changes: This summary was created with assistance from AI and may have inaccuracies. For accurate information, please refer to the original source documents linked here.
Thank you to arxiv for use of its open access interoperability.
Reference Links
- https://doi.org/10.5281/zenodo.7614908
- https://doi.org/10.17894/ucph.e3d897af-233a-4f01-a893-7b0fad1f66c2
- https://doi.org/10.5281/zenodo.7143382
- https://www.stsci.edu/hst/instrumentation/wfc3/data-analysis/psf
- https://github.com/gbrammer/eazy-py
- https://github.com/gbrammer/eazy-photoz/tree/master/templates/sfhz
- https://doi.org/10.17909/g3nt-a370