The Low End of the Initial Mass Function in Young LMC Clusters: I. The Case of R136

Abstract

We report the result of a study in which we have used very deep broadband V and I WFPC2 images of the R136 cluster in the Large Magellanic Cloud from the HST archive, to sample the luminosity function below the detection limit of 2.8 Mo previously reached. In these new deeper images, we detect stars down to a limiting magnitude of m_F555W = 24.7 (~ 1 magnitude deeper than previous works), and identify a population of red stars evenly distributed in the surrounding of the R136 cluster. A comparison of our color-magnitude diagram with recentely computed evolutionary tracks indicates that these red objects are pre-main sequence stars in the mass range 0.6 - 3 Mo. We construct the initial mass function (IMF) in the 1.35 - 6.5 Mo range and find that, after correcting for incompleteness, the IMF shows a definite flattening below ~ 2 Mo. We discuss the implications of this result for the R136 cluster and for our understanding of starburst galaxies formation and evolution in general.

29 pages, 6 tables, 11 figures included + 3 external files, accepted for publication by Ap.J

Cited by in corpus (72)

• On the variation of the Initial Mass Function
• Embedded Clusters in Molecular Clouds
• The Initial Mass Function of Stars: Evidence for Uniformity in Variable Systems
• Toward Understanding Massive Star Formation
• A Universal Stellar Initial Mass Function? A Critical Look at Variations
• The nature of faint submm-selected galaxies
• The maximum stellar mass, star-cluster formation and composite stellar populations
• The galaxy stellar mass-star formation rate relation: Evidence for an evolving stellar initial mass function?
• Surface Brightness Profiles and Structural Parameters for 53 Rich Stellar Clusters in the Large Magellanic Cloud
• The Initial Mass Function of Low-Mass Stars and Brown Dwarfs in Young Clusters
• On the massive stellar population of the Super Star Cluster Westerlund 1
• The stellar and sub-stellar IMF of simple and composite populations
• The relation between the most-massive star and its parental star cluster mass
• The Variation of Integrated Star IMFs among Galaxies
• Mass segregation and fractal substructure in young massive clusters: (I) the McLuster code and method calibration
• The Initial Mass Function of the Massive Star-forming Region NGC 3603 from Near-Infrared Adaptive Optics observations
• M82-F: A Doomed Super Star Cluster?
• A Possible Origin of the Mass-Metallicity Relation of Galaxies
• The Nature of Starburst Activity in M82
• Thickening of galactic disks through clustered star formation
• On the Evolutionary History of Stars and their Fossil Mass and Light
• Extended Main Sequence Turnoffs in Intermediate-Age Star Clusters: A Correlation Between Turnoff Width and Early Escape Velocity
• Star Formation in the Field and Clusters of NGC 5253
• The mmax-Mecl relation, the IMF and IGIMF: probabilistically sampled functions?
• Super Star Cluster Velocity Dispersions and Virial Masses in the M82 Nuclear Starburst
• Mass Segregation in Young Magellanic Clouds Star Clusters: Four Clusters observed with HST
• Past and present star formation in the SMC: NGC 346 and its neighborhood
• The galaxy-wide IMF of dwarf late-type to massive early-type galaxies
• On the Constancy of the Characteristic Mass of Young Stars
• The low-mass Initial Mass Function in the 30 Doradus starburst cluster
• Star formation in 30 Doradus
• Photometric determination of the mass accretion rates of pre-main sequence stars. I. Method and application to the SN1987A field
• B Star Rotational Velocities in h and chi Persei: A Probe of Initial Conditions During the Star-Formation Process
• Hubble Tarantula Treasury Project: Unraveling Tarantula's Web. II. Optical and Near Infrared Star Formation History of the Starburst Cluster NGC 2070 in 30 Doradus
• The Stellar Mass Distribution in the Giant Star Forming Region NGC 346
• Structure and Mass of a Young Globular Cluster in NGC 6946
• On the fraction of intermediate-mass close binaries that explode as type-Ia supernovae
• The Stellar Population and Star Clusters in the Unusual Local Group Galaxy IC 10
• The influence of multiple stars on the high-mass stellar initial mass function and age-dating of young massive star clusters
• HST/NICMOS detection of a partially embedded, intermediate-mass pre-main-sequence population in the 30 Doradus Nebula
• An IMF Study of the Dwarf Starburst Galaxy NGC 4214
• Testing the universality of the IMF with Bayesian statistics: young clusters
• High mass X-ray binaries in the LMC: dependence on the stellar population age and the "propeller" effect
• Hubble Tarantula Treasury Project. IV. The extinction law
• A dozen colliding wind X-ray binaries in the star cluster R136 in the 30Doradus region
• The Effect of Star Formation History on the Inferred Initial Stellar Mass Function
• Top-heavy integrated galactic stellar initial mass functions (IGIMFs) in starbursts
• The Magellanic Bridge cluster NGC 796: Deep optical AO imaging reveals the stellar content and initial mass function of a massive open cluster
• The Initial Mass Function of the Stellar Association NGC 602 in the Small Magellanic Cloud with Hubble Space Telescope ACS Observations
• On the infant weight loss of low- to intermediate-mass star clusters
• Anatomy of a post-starburst minor merger: a multi-wavelength WFC3 study of NGC 4150
• Big Fish in Small Ponds: Massive Stars in the Low Mass Clusters of M83
• A Database of 2MASS Near-Infrared Colors of Magellanic Cloud Star Clusters
• Sampling methods for stellar masses and the mmax-Mecl relation in the starburst dwarf galaxy NGC 4214
• Evolution of dust and molecular hydrogen in the Magellanic System
• Photometric determination of the mass accretion rates of pre-main sequence stars. V. Recent star formation in the 30 Dor nebula
• The low-mass pre-main sequence population of the stellar association LH 52 in the Large Magellanic Cloud discovered with Hubble Space Telescope WFPC2 Observations
• L-band (3.5 micron) IR-excess in massive star formation, I. 30 Doradus
• The Initial Mass Function toward the low-mass end in the Large Magellanic Cloud with HST/WFPC2 Observations
• Mass function of a young cluster in a low-metallicity environment. Sh 2-209
• Uncrowding R 136 from VLT-SPHERE extreme adaptive optics
• Low-mass pre--main-sequence stars in the Magellanic Clouds
• VLT-MAD observations of the core of 30 Doradus
• Low Mass Pre-Main Sequence stars in the Large Magellanic Cloud - II: HST-WFPC2 observations of two fields in the 30 Doradus region
• Microlensing at Cosmological Distances: Event Rate Predictions in the Warhol Arc of MACS 0416
• A Code to Make Your Own Synthetic ObservaTIonS (MYOSOTIS)
• Is the young star cluster NGC 376 dissolving in the field of the SMC?
• Magellanic System Stars Identified in SMACS J0723.3-7327 James Webb Space Telescope Early Release Observations Images
• The Starburst IMF -- An Impossible Measurement?
• Using the Modified Lognormal Power Law Distribution to Model the Mass Function of NGC 1711
• The Future of IMF studies with the ELT and MICADO I: The local Universe as a resolved IMF laboratory
• The star formation process in the Magellanic Clouds