JWST photometry of globular cluster populations in MACS0417.5−1154

Harris, William E. (author), Bradač, Maruša (author), Martis, Nicholas S. (author)

Deep JWST imaging of the massive galaxy cluster MACS0417.5−1154, at redshift z = 0.443, reveals a huge population of globular clusters (GCs) and ultracompact dwarfs (UCDs) primarily distributed around its single central giant brightest cluster galaxy (BCG). We present Near-Infrared Camera (NIRCam)/short-wavelength channel photometry of the GC system in four bands (F090W, F115W, F150W, and F200W). The spatial distribution of the system matches well in radial and ellipticity profile with the high elongation (b/a ≃ 0.5) of the BCG halo light. The total GC population within MACS0417 is estimated to be near 1.5 × 10$^5$, similar to the systems in Abell 2744, Coma, and other galaxy clusters with comparable masses. With similar results for GC photometry in hand from other lensing clusters at a range of redshifts, it is now possible to trace, on purely observational grounds, the luminosity evolution of GC systems over many gigayears of lookback time, as seen through their color–magnitude diagrams. We show this sequence for five systems reaching lookback times of more than 7 Gyr. A systematic change in the GC/UCD sequence with lookback time is clearly visible, near what is expected for age-fading of a simple stellar population with time. Lastly, we evaluate the effectiveness of the various JWST NIRCam filters for broadband photometry of GC systems as a function of redshift as an aid to planning further studies.

• Language: English
• Keywords: astrophysics, galaxy clusters
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FMF - Faculty of Mathematics and Physics
• Publication status: Published
• Publication version: Version of Record
• Year: 2025
• Number of pages: 13 str.
• Numbering: Vol. 993, no. 2
• PID: 20.500.12556/RUL-176506
• UDC: 524.8
• ISSN on article: 1538-4357
• DOI: 10.3847/1538-4357/ae073f
• COBISS.SI-ID: 259612163
• Publication date in RUL: 02.12.2025

Record is a part of a journal

• Title: The Astrophysical journal
• Shortened title: Astrophys. j.
• Publisher: University of Chicago Press for the American Astronomical Society
• ISSN: 1538-4357
• COBISS.SI-ID: 515079705

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: astrofizika, jate galaksij