The dynamical age of the LMC globular cluster NGC 1835 using the "dynamical clock"

Fuente: arXiv
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Main Authors: Giusti, Camilla, Cadelano, Mario, Ferraro, Francesco R., Lanzoni, Barbara, Pallanca, Cristina, Vesperini, Enrico, Dalessandro, Emanuele, Salaris, Maurizio
Format: Preprint
Published: 2024
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_version_ 1866913452227821568
author Giusti, Camilla
Cadelano, Mario
Ferraro, Francesco R.
Lanzoni, Barbara
Pallanca, Cristina
Vesperini, Enrico
Dalessandro, Emanuele
Salaris, Maurizio
author_facet Giusti, Camilla
Cadelano, Mario
Ferraro, Francesco R.
Lanzoni, Barbara
Pallanca, Cristina
Vesperini, Enrico
Dalessandro, Emanuele
Salaris, Maurizio
contents In the context of the study of the size-age relationship observed in star clusters in the Large Magellanic Cloud and the investigation of its origin, here we present the determination of the structural parameters and the dynamical age of the massive cluster NGC 1835. We have used a powerful combination of optical and near-ultraviolet images acquired with the WFC3 onboard the HST to construct the star density profile from resolved star counts, determining the values of the core, half-mass and tidal radii through the 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 central segregation of blue stragglers stars (BSSs) within the cluster half-mass radius by means of the A+ 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 A+ ($0.30\pm 0.04$) is the largest measured so far in the LMC clusters, providing evidence of a highly dynamically evolved stellar system. NGC 1835 nicely fits into the correlation between A+ and the central relaxation time and in the anti-correlation between A+ and the core radius defined by the Galactic and the Magellanic Cloud clusters investigated to date.
format Preprint
id arxiv_https___arxiv_org_abs_2405_04922
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The dynamical age of the LMC globular cluster NGC 1835 using the "dynamical clock"
Giusti, Camilla
Cadelano, Mario
Ferraro, Francesco R.
Lanzoni, Barbara
Pallanca, Cristina
Vesperini, Enrico
Dalessandro, Emanuele
Salaris, Maurizio
Astrophysics of Galaxies
Solar and Stellar Astrophysics
In the context of the study of the size-age relationship observed in star clusters in the Large Magellanic Cloud and the investigation of its origin, here we present the determination of the structural parameters and the dynamical age of the massive cluster NGC 1835. We have used a powerful combination of optical and near-ultraviolet images acquired with the WFC3 onboard the HST to construct the star density profile from resolved star counts, determining the values of the core, half-mass and tidal radii through the 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 central segregation of blue stragglers stars (BSSs) within the cluster half-mass radius by means of the A+ 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 A+ ($0.30\pm 0.04$) is the largest measured so far in the LMC clusters, providing evidence of a highly dynamically evolved stellar system. NGC 1835 nicely fits into the correlation between A+ and the central relaxation time and in the anti-correlation between A+ and the core radius defined by the Galactic and the Magellanic Cloud clusters investigated to date.
title The dynamical age of the LMC globular cluster NGC 1835 using the "dynamical clock"
topic Astrophysics of Galaxies
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2405.04922