Star cluster formation history along the minor axis of the Large Magellanic Cloud

A.E. PIATTI, A.A. COLE, B. EMPTAGE

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2018 vol. 473 p. 105 - 115

0035-8711

along the minor axis of the LMC, from the LMC optical centreup to $sim$ 39 degrees outwards to the North-West. The data base was exploited in order to search for new star cluster candidates,to produce cluster CMDs cleaned from field star contamination and to derive ageestimates for a statistically complete cluster sample.We confirmed  that 146 starcluster candidates are genuine physical systems, and concluded that an overall $sim$30 per cent of catalogued clusters in the surveyed regions are unlikely to be true physical systems. We did not find any new cluster candidates in the outskirts of the LMC (deprojected distance$ga$ 8 degrees). The derived ages of the studied clusters are in the range 7.2< log($t$ yr$^{-1}$) $le$ 9.4, with the sole exception of the globular cluster NGC,1786 (log($t$ yr$^{-1}$) = 10.10).We also calculated the cluster frequency for each region, from which we confirmed previously proposed outside-in formation scenarios. In addition, we found that the outer LMC fields show a sudden episode of cluster formation (log($t$ yr$^{-1}$) $sim$ 7.8-7.9) that continued untillog($t$ yr$^{-1}$) $sim$ 7.3 only in the outermost LMC region. We link these featuresto the first pericentre passage of the LMC to the MW, which could have triggeredcluster formation due to ram pressure interaction between the LMC and MW halo.