Age calibration and age distribution for rich star clusters in the Large Magellanic Cloud

1985 ◽  
Vol 299 ◽  
pp. 211 ◽  
Author(s):  
R. A. W. Elson ◽  
S. M. Fall
2018 ◽  
Vol 616 ◽  
pp. A187 ◽  
Author(s):  
P. K. Nayak ◽  
A. Subramaniam ◽  
S. Choudhury ◽  
Ram Sagar

Aims. We aim to estimate the age and reddening parameters of already identified star clusters within the Small Magellanic Cloud (SMC) in a consistent way using available photometric data, classify them based on their mass and strength, and study their spatiotemporal distribution. Methods. We have used a semi-automated quantitative method, developed in the first paper of this series (Paper I), to estimate the cluster parameters using the V and I band photometric data from the Optical Gravitational Lensing Experiment (OGLE) III survey. Results. We estimated parameters of 179 star clusters (17 are newly parameterised) and classified them into four groups. We present an online catalogue of parameters as well as cleaned and isochrone-fitted colour magnitude diagrams of 179 clusters. We compiled age information of 468 clusters by combining previous studies with our catalogue, to study their spatio-temporal distribution. Most of the clusters located in the southern part of the SMC are in the age range 600 Myr–1.25 Gyr, whereas, the clusters younger than 100 Myr are mostly found in the northern SMC, with the central SMC showing continuous cluster formation. The peak of the cluster age distribution is identified at 130 ± 35 Myr, very similar to the Large Magellanic Cloud (LMC) in Paper I. Conclusions. We suggest that the burst of cluster formation at 130 Myr is due to the most recent LMC-SMC interaction. 90% of the studied sample is found to have mass < 1700 M⊙, suggesting that the SMC is dominated by low mass clusters. There is tentative evidence for compact clusters in the LMC when compared to those in the Galaxy and the SMC. A progressive shifting of cluster location from the south to north of the SMC is identified in last ~600 Myr. The details of spatio-temporal distribution of clusters presented in two videos as part of this study can be used as a tool to constrain details of the recent LMC-SMC interactions.


1991 ◽  
Vol 148 ◽  
pp. 193-194
Author(s):  
M. Alongi ◽  
C. Chiosi

We present the age distribution function for Large Magellanic Cloud (LMC) clusters obtained from a relationship between their integrated U BV colours and age. We discuss further the results by Chiosi et al. (1988) on the nature of the bimodal distribution of the (B - V) colours for LMC clusters. Their conclusion that bimodality in the colour stems from the combined effect of the age distribution function and the rate at which clusters change colour with age, is revisited. The result of our analysis shows that the age distribution is the sole agent and that a real age gap is present. Finally, we draw some conclusions about the efficiency of cluster formation and disruption in the LMC.


2016 ◽  
Vol 586 ◽  
pp. A41 ◽  
Author(s):  
T. Palma ◽  
L. V. Gramajo ◽  
J. J. Clariá ◽  
M. Lares ◽  
D. Geisler ◽  
...  

2020 ◽  
Vol 498 (1) ◽  
pp. 205-222
Author(s):  
João F C Santos ◽  
Francisco F S Maia ◽  
Bruno Dias ◽  
Leandro de O Kerber ◽  
Andrés E Piatti ◽  
...  

ABSTRACT We provide a homogeneous set of structural parameters of 83 star clusters located at the periphery of the Small Magellanic Cloud (SMC) and the Large Magellanic Cloud (LMC). The clusters’ stellar density and surface brightness profiles were built from deep, AO assisted optical images, and uniform analysis techniques. The structural parameters were obtained from King and Elson et al. model fittings. Integrated magnitudes and masses (for a subsample) are also provided. The sample contains mostly low surface brightness clusters with distances between 4.5 and 6.5 kpc and between 1 and 6.5 kpc from the LMC and SMC centres, respectively. We analysed their spatial distribution and structural properties, comparing them with those of inner clusters. Half-light and Jacobi radii were estimated, allowing an evaluation of the Roche volume tidal filling. We found that: (i) for our sample of LMC clusters, the tidal radii are, on average, larger than those of inner clusters from previous studies; (ii) the core radii dispersion tends to be greater for LMC clusters located towards the southwest, with position angles of ∼200° and about ∼5° from the LMC centre, i.e. those LMC clusters nearer to the SMC; (iii) the core radius evolution for clusters with known age is similar to that of inner clusters; (iv) SMC clusters with galactocentric distances closer than 4 kpc are overfilling; (v) the recent Clouds collision did not leave marks on the LMC clusters’ structure that our analysis could reveal.


1991 ◽  
Vol 148 ◽  
pp. 219-221
Author(s):  
A. Vallenari ◽  
C. Chiosi ◽  
G. Bertelli ◽  
G. Meylan ◽  
S. Ortolani

We present the photometry of two clusters NGC 2164 and NGC 1850 located in the Large Magellanic Cloud (LMC). The ages are determined taking into account the presence either of convective overshoot or of semiconvection in the stellar models. The experimental luminosity functions are compared with the theoretical models.


1991 ◽  
Vol 148 ◽  
pp. 161-164 ◽  
Author(s):  
S. van den Bergh

Star clusters in the Magellanic Clouds (MCs) differ from those in the Galaxy in a number of respects: (1) the Clouds contain a class of populous open clusters that has no Galactic counterpart; (2) Cloud clusters have systematically larger radii rh than those in the Galaxy; (3) clusters of all ages in the Clouds are, on average, more flattened than those in the Galaxy. In the Large Magellanic Cloud (LMC) there appear to have been two distinct epochs of cluster formation. LMC globulars have ages of 12-15 Gyr, whereas most populous open clusters have ages <5 Gyr. No such dichotomy is observed for clusters in the Small Magellanic Cloud (SMC) The fact that the SMC exhibits no enhanced cluster formation at times of bursts of cluster formation in the LMC, militates against encounters between the Clouds as a cause for enhanced rates of star and cluster formation.


2005 ◽  
Vol 129 (6) ◽  
pp. 2701-2713 ◽  
Author(s):  
Marc Rafelski ◽  
Dennis Zaritsky

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