Cluster Mass Functions in the Large and Small Magellanic Clouds: Fading and Size-of-Sample Effects

By D. Hunter, Bruce G. Elmegreen, T. Dupuy, M. Mortonson. 2003

194 citations recorded by the source corpus.

The properties of ∼939 star clusters in the Large and Small Magellanic Clouds were determined from ground-based CCD images in UBVR passbands. The areal coverage was extensive, corresponding to 11.0 kpc2 in the LMC and 8.3 kpc2 in the SMC. After corrections for reddening, the colors and magnitudes of the clusters were converted to ages and masses, and the resulting mass distributions were searched for the effects of fading, evaporation, and size-of-sample bias. The data show a clear signature of cluster fading below the detection threshold. The initial cluster mass function (ICMF) was determined by fitting the mass and age distributions with cluster population models. These models suggest a new method to determine the ICMF that is nearly independent of fading or disruption and is based on the slope of a correlation between age and the maximum cluster mass in equally spaced intervals of log age. For a nearly uniform star formation rate, this correlation has a slope equal to 1/(α - 1) for an ICMF of dn(M)/dM ∝ M-α. We determine that α is between 2 and 2.4 for the LMC and SMC using this method plus another method in which models are fitted to the mass distribution integrated over age and to the age distribution integrated over mass. The maximum mass method also suggests that the cluster formation rate in the LMC age gap between 3 and 13 Gyr is about a factor of 10 below that in the period from 0.1 to 1 Gyr. The oldest clusters correspond in age and mass to halo globular clusters in the Milky Way. They do not fit the trends for lower mass clusters but appear to be a separate population that either had a very high star formation rate and became depleted by evaporation or formed with only high masses.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/b352739971db7527c8ceb965b7e10de567a065cd

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Citations in the corpus

The Variation of Integrated Star Initial Mass Functions among Galaxies (2005, background): “For embedded stellar clusters in the solar neighborhood with masses between 50 and 1000M , Lada & Lada (2003) find a slope ¼ 2, while Hunter et al. (2003) find 2P P 2:4 for 103PMecl/M P 104 in the SMC and LMC, and Zhang & Fall (1999) find 1:95 0:03 for 104PMecl/M P106 in the Antennae galaxies.”
The mass function of young star clusters in spiral galaxies (2008, background): “Excluding the old GCs, the most massive clusters in the LMC have masses of ≈2 × 105 M (Hunter et al. 2003; Anders & de Grijs 2006), and the MF can be well fitted by a power-law with slope α = −2.”
THE SECOND SURVEY OF THE MOLECULAR CLOUDS IN THE LARGE MAGELLANIC CLOUD BY NANTEN. II. STAR FORMATION (2009, background): “Their masses are ∼104–105 M , which are smaller than those of the Galactic globular clusters but larger than those of the Galactic open clusters by an order of magnitude (Kumai et al. 1993; Hunter et al. 2003).”
An analytical description of the disruption of star clusters in tidal fields with an application to Galactic open clusters (2005, background): “The observed mass upper limit is probably determined by statistical effects (Hunter et al. 2003; Gieles et al. 2005b).”
On the star formation rate – brightest cluster relation: estimating the peak star formation rate in post-merger galaxies (2008, methodology): “For example, Hunter et al. (2003) used the relation of the most massive cluster per logarithmic age bin in the Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC) in order to estimate the exponent of the cluster initial mass function (IMF; α).”
Probing the role of the galactic environment in the formation of stellar clusters, using M83 as a test bench (2015, background): “Massive clusters are statistically more likely to be older because the galaxy has had a longer c© 2015 RAS period of time to sample the high mass bins of the ICMF (Hunter et al. 2003).”
The maximum stellar mass, star-cluster formation and composite stellar populations (2005, background): “…universal form of the ECMF: Lada & Lada (2003) find a slope β = 2 in the solar neighbourhood for clusters with masses between 50 and 1000 M , while Hunter et al. (2003) find 2 β 2.4 for 103 M ecl/M 104 in the Small Magellanic Cloud (SMC) and Large Magellanic Cloud (LMC), and Zhang & Fall (1999)…”
THE ANTENNAE GALAXIES (NGC 4038/4039) REVISITED: ADVANCED CAMERA FOR SURVEYS AND NICMOS OBSERVATIONS OF A PROTOTYPICAL MERGER (2010, background): “…studies have also found that the young cluster mass function (MF) in a variety of galaxies is a power law of the form φ(M)dM ∝ MβdM with a value of β ≈ −2 (e.g., Zhang & Fall 1999 in the Antennae; Hunter et al. 2003 in the Magellanic Clouds; Bik et al. 2003 in M51; and Chandar et al. 2010 in M83).”
Star Cluster Demographics. I. A General Framework and Application to the Antennae Galaxies (2006, background): “…themass and luminosity functions in the Antennae [i.e., (M )dM / M dM with a value of 2; Zhang & Fall 1999; Fall 2004; S. M. Fall et al. 2007, in preparation] and the Small and Large Magellanic Clouds (SMC and LMC) (Hunter et al. 2003), as well as a few other galaxies (see review by Larsen 2007).”
Galactic-Field Initial Mass Functions of Massive Stars (2003, background): “Hunter et al. (2003) find =2–2.4 for the initial cluster mass function in the Large and Small Magellanic Clouds, and Zhang & Fall (1999) report ¼ 2 0:08 for young star clusters with 104dMecl=M d106 in the Antennae galaxies.”
The formation of very wide binaries during the star cluster dissolution phase (2010, background): “The initial cluster mass distribution may be approximated byf (M) ∝ M−γ with γ ≈ 2 (see, e.g., Zhang & Fall 1999; Ashman & Zepf 2001; Bik et al. 2003; Hunter et al. 2003).”
AGE DETERMINATION OF SIX INTERMEDIATE-AGE SMALL MAGELLANIC CLOUD STAR CLUSTERS WITH HST/ACS (2008, unknown): “Furthermore, the intermediateage clusters in the SMC might survive for a Hubble time, due to their high mass and the structure of the SMC (no bulge or disk to be passed) (Hunter et al. 2003; Lamers et al. 2005; Gieles et al. 2007).”
Implications for the formation of star clusters from extragalactic star formation rates (2004, methodology): “For example, Hunter et al. (2003) find 2 < β < 2.4 for a sample of 939 LMC and SMC clusters after applying corrections for redding, fading, evaporation and size-of-sample effects.”
Mean proper motions, space orbits, and velocity dispersion profiles of Galactic globular clusters derived fromGaiaDR2 data (2018, unknown): “We can also fit the cluster distribution by a power-law mass distribution N(m) ∼ MβGC , with β = −2.0, similar to that seen for young star clusters in the Milky Way and other nearby galaxies (Hunter et al. 2003; Gieles et al. 2006; Baumgardt et al. 2013).”