Issue |
A&A
Volume 690, October 2024
|
|
---|---|---|
Article Number | A315 | |
Number of page(s) | 24 | |
Section | Extragalactic astronomy | |
DOI | https://doi.org/10.1051/0004-6361/202449543 | |
Published online | 18 October 2024 |
COSMOS brightest group galaxies
III. Evolution of stellar ages
1
Department of Computer Science, Aalto University, PO Box 15400
Espoo, 00 076
Finland
2
Department of Physics, University of Helsinki, PO Box 64
00014
Helsinki, Finland
3
Department of Physics and Astronomy, University of Victoria, Victoria, BC, V8X 4M6
Canada
4
Infosys Visiting Chair Professor, Indian Institute of Science, Bangalore, 560012
India
5
International Space Science Institute (ISSI), Hallerstr. 6, CH-3012
Bern, Switzerland
6
Thüringer Landessternwarte, Sternwarte 5, 07778
Tautenburg, Germany
7
Caltech/IPAC, 1200 E. California Blvd., Pasadena, CA, 91125
USA
8
Cosmic Dawn Center (DAWN)
9
Niels Bohr Institute, University of Copenhagen, Jagtvej 128, 2200
Copenhagen, Denmark
10
The University of Texas at Austin, 2515 Speedway Boulevard Stop C1400, Austin, TX, 78712
USA
11
DTU-Space, Technical University of Denmark, Elektrovej 327, DK2800
Kgs. Lyngby, Denmark
12
Laboratoire d’Astrophysique de Marseille, 38 rue Frederic Joliot Curie, 13388
Marseille, France
13
Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU, WPI), UTIAS, Tokyo Institutes for Advanced Study, University of Tokyo, Chiba, 277-8583
Japan
14
Department of Astronomy, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-0033
Japan
15
Center for Data-Driven Discovery, Kavli IPMU (WPI), UTIAS, The University of Tokyo, Kashiwa, Chiba, 277-8583
Japan
16
Universitäts-Sternwarte, Fakultät für Physik, Ludwig-Maximilians-Universität München, Scheinerstr.1, 81679
München, Germany
17
Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Straße 1, 85741
Garching, Germany
18
Dipartimento di Fisica e Astronomia, Alma Mater Studiorum Università di Bologna, Via Gobetti 93/2, 40129
Bologna, Italy
19
INAF – Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Gobetti 93/3, 40129
Bologna, Italy
20
Zentrum für Astronomie, Universität Heidelberg, Philosophenweg 12, 69120
Heidelberg, Germany
21
Department of Physics and Astronomy, University of California Riverside, Pierce Hall, Riverside, CA, 92521
USA
22
Departamento de Física Teórica, M-8, Universidad Autónoma de Madrid, Cantoblanco, E-28049
Madrid, Spain
23
Centro de Investigación Avanzada en Física Fundamental (CIAFF), Universidad Autónoma de Madrid, Cantoblanco, 28049
Madrid, Spain
24
Center for Computational Astrophysics, Flatiron Institute, 162 Fifth Ave, New York, NY, 10010
USA
25
IAASARS, National Observatory of Athens, Lofos Nymfon, 11851
Athens, Greece
Received:
8
February
2024
Accepted:
2
August
2024
The unique characteristics of the brightest group galaxies (BGGs) serve as a link in the evolutionary continuum between galaxies such as the Milky Way and the more massive brightest cluster galaxies found in dense clusters. This research investigates the evolution of the stellar properties of BGGs over cosmic time (z = 0.08 − 1.30), extending the work from our prior studies. We analyzed the data of 246 BGGs selected from our X-ray galaxy group catalog within the COSMOS field, examining stellar age, mass, star-formation rate (SFR), specific SFR, and halo mass. We compared observations with the Millennium and Magneticum simulations. Additionally, we investigated whether stellar properties vary with the projected offset from the X-ray peak or the hosting halo center. We evaluated the accuracy of SED-derived stellar ages using a mock galaxy catalog, finding a mean absolute error of around 1 Gyr. Interestingly, the observed BGG age distributions exhibit a bias toward younger intermediate ages compared to both semi-analytical models and the Magneticum simulation. Our analysis of stellar age versus mass unveils intriguing trends with a positive slope, hinting at complex evolutionary pathways across redshifts. We observed a negative correlation between stellar age and SFR across all redshift ranges. We employed a cosmic time dependent main sequence framework to identify star forming BGGs and find that approximately 20% of BGGs in the local universe continue to exhibit characteristics typical of star forming galaxies, with this proportion increasing to 50% at z = 1.0. Our findings support an inside-out formation scenario for BGGs, where older stellar populations reside near the X-ray peak and younger populations at larger offsets indicate ongoing star-formation. The observed distribution of stellar ages, particularly for lower-mass BGGs in the range of 1010−11 M⊙, deviates from the constant ages predicted by the models across all stellar mass ranges and redshifts. This discrepancy aligns with the current models’ known limitations in accurately capturing galaxies’ complex star-formation histories.
Key words: galaxies: clusters: general / galaxies: evolution / galaxies: groups: general / galaxies: star formation / galaxies: statistics / galaxies: stellar content
© The Authors 2024
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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