|Authors||Richard de Grijs (1), Nate Bastian (2), Henny J.G.L.M. Lamers (2)|
|Affiliation||1 Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK|
2 Astronomical Institute, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands
|Submitted to||Monthly Notices of the Royal Astronomical Society|
Adopting the expression for the cluster disruption time-scale of dis(M)= disref (M/104 Mo)gamma with gamma ~0.62 (Paper I), we find that the ratios between the real cluster formation rates in the pre-burst phase (log(t/yr) > 9.4), the burst-phase (8.4 < log(t/yr) < 9.4) and the post-burst phase (log(t/yr) < 8.4) are about 1:2:1/40. The formation rate during the burst may have been higher if the actual duration of the burst was shorter than adopted.
The mass distribution of the clusters formed during the burst shows a turnover at log(Mcl/Mo) ~5.3 which is not caused by selection effects. This distribution can be explained by cluster formation with an initial power-law mass function of slope alpha=2 up to a maximum cluster mass of Mmax = 3 x 106 Mo, and cluster disruption with a normalisation time-scale disref / burst=(3.0 ± 0.3) x 10-2. For a burst age of 1 x 109 yr, we find that the disruption time-scale of a cluster of 104 Mo is disref ~ 3 x 107 years, with an uncertainty of approximately a factor of two. This is the shortest disruption time-scale known in any galaxy.