| Issue |
A&A
Volume 687, July 2024
|
|
|---|---|---|
| Article Number | A310 | |
| Number of page(s) | 10 | |
| Section | Galactic structure, stellar clusters and populations | |
| DOI | https://doi.org/10.1051/0004-6361/202450088 | |
| Published online | 30 July 2024 | |
Determining the dynamical age of the LMC globular cluster NGC 1835 using the ‘dynamical clock’
Star density profile and blue straggler stars⋆,⋆⋆
1
Dipartimento di Fisica & Astronomia, Università degli Studi di Bologna, Via Gobetti 93/2, 40129 Bologna, Italy
e-mail: camilla.giusti3@unibo.it
2
INAF – Astrophysics and Space Science Observatory Bologna, Via Gobetti 93/3, 40129 Bologna, Italy
3
Dept. of Astronomy, Indiana University, Bloomington, IN 47401, USA
4
Astrophysics Research Institute, Liverpool John Moores University, Liverpool L3 5RF, UK
Received:
22
March
2024
Accepted:
8
May
2024
In the context of the study of the size–age relationship observed in star clusters in the Large Magellanic Cloud (LMC) and the investigation of its origin, we present the determination of the structural parameters and the dynamical age of the massive cluster NGC 1835. We used the powerful combination of optical and near-ultraviolet images acquired with the WFC3 on board the HST to construct the star density profile from resolved star counts, determining the values of the core, half-mass, and tidal radii through comparison with the King model family. The same data also allowed us to evaluate the dynamical age of the cluster by using the ‘dynamical clock’. This is an empirical method that quantifies the level of the central segregation of blue stragglers stars (BSSs) within the cluster half-mass radius by means of the Arh+ parameter, which is defined as the area enclosed between the cumulative radial distribution of BSSs and that of a reference (lighter) population. The results confirm that NGC 1835 is a very compact cluster with a core radius of only 0.84 pc. The estimated value of Arh+ (0.30 ± 0.04) is the largest measured so far in the LMC clusters, providing evidence of a highly dynamically evolved stellar system. NGC 1835 fits nicely into the correlation between Arh+ and the central relaxation time and in the anti-correlation between Arh+ and the core radius defined by the Galactic and Magellanic Cloud clusters investigated to date.
Key words: blue stragglers / Hertzsprung–Russell and C–M diagrams / Magellanic Clouds / galaxies: star clusters: general
The data output are available at the CDS via anonymous ftp to https://cdsarc.cds.unistra.fr (130.79.128.5) or via https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/687/A310
© 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.
This article is published in open access under the Subscribe to Open model. Subscribe to A&A to support open access publication.
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.